diff --git a/package.json b/package.json
index 0f1aa7db9..588807ccd 100644
--- a/package.json
+++ b/package.json
@@ -27,6 +27,7 @@
     "body-parser": "^1.15.2",
     "chance": "^1.0.4",
     "cheerio": "^0.22.0",
+    "clean-webpack-plugin": "^4.0.0",
     "compression": "^1.6.2",
     "connect-flash": "^0.1.1",
     "connect-session-sequelize": "^7.1.2",
diff --git a/webpack.common.js b/webpack.common.js
index 98a2bfc16..5cf99d1bc 100644
--- a/webpack.common.js
+++ b/webpack.common.js
@@ -3,6 +3,7 @@ const path = require('path')
 const HtmlWebpackPlugin = require('html-webpack-plugin')
 const CopyWebpackPlugin = require('copy-webpack-plugin')
 const MiniCssExtractPlugin = require('mini-css-extract-plugin')
+const {CleanWebpackPlugin} = require("clean-webpack-plugin");
 
 // Fix possible nofile-issues
 const fs = require('fs')
@@ -12,6 +13,7 @@ gracefulFs.gracefulify(fs)
 module.exports = {
   name: 'app',
   plugins: [
+    new CleanWebpackPlugin(),
     new webpack.ProvidePlugin({
       Visibility: 'visibilityjs',
       Cookies: 'js-cookie',
diff --git a/yarn.lock b/yarn.lock
index caba51e40..e1e5bdb39 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -427,6 +427,14 @@
   resolved "https://registry.yarnpkg.com/@types/geojson/-/geojson-7946.0.10.tgz#6dfbf5ea17142f7f9a043809f1cd4c448cb68249"
   integrity sha512-Nmh0K3iWQJzniTuPRcJn5hxXkfB1T1pgB89SBig5PlJQU5yocazeu4jATJlaA0GYFKWMqDdvYemoSnF2pXgLVA==
 
+"@types/glob@^7.1.1":
+  version "7.2.0"
+  resolved "https://registry.yarnpkg.com/@types/glob/-/glob-7.2.0.tgz#bc1b5bf3aa92f25bd5dd39f35c57361bdce5b2eb"
+  integrity sha512-ZUxbzKl0IfJILTS6t7ip5fQQM/J3TJYubDm3nMbgubNNYS62eXeUpoLUC8/7fJNiFYHTrGPQn7hspDUzIHX3UA==
+  dependencies:
+    "@types/minimatch" "*"
+    "@types/node" "*"
+
 "@types/hast@^2.0.0":
   version "2.3.4"
   resolved "https://registry.yarnpkg.com/@types/hast/-/hast-2.3.4.tgz#8aa5ef92c117d20d974a82bdfb6a648b08c0bafc"
@@ -509,6 +517,11 @@
   resolved "https://registry.yarnpkg.com/@types/mime/-/mime-3.0.1.tgz#5f8f2bca0a5863cb69bc0b0acd88c96cb1d4ae10"
   integrity sha512-Y4XFY5VJAuw0FgAqPNd6NNoV44jbq9Bz2L7Rh/J6jLTiHBSBJa9fxqQIvkIld4GsoDOcCbvzOUAbLPsSKKg+uA==
 
+"@types/minimatch@*":
+  version "5.1.2"
+  resolved "https://registry.yarnpkg.com/@types/minimatch/-/minimatch-5.1.2.tgz#07508b45797cb81ec3f273011b054cd0755eddca"
+  integrity sha512-K0VQKziLUWkVKiRVrx4a40iPaxTUefQmjtkQofBkYRcoaaL/8rhwDWww9qWbrgicNOgnpIsMxyNIUM4+n6dUIA==
+
 "@types/ms@*":
   version "0.7.31"
   resolved "https://registry.yarnpkg.com/@types/ms/-/ms-0.7.31.tgz#31b7ca6407128a3d2bbc27fe2d21b345397f6197"
@@ -784,7 +797,6 @@
 
 "Idle.Js@git+https://github.com/shawnmclean/Idle.js":
   version "0.0.1"
-  uid "2b57cc6e49d177b7ddce0cca00ef5cbe07453541"
   resolved "git+https://github.com/shawnmclean/Idle.js#2b57cc6e49d177b7ddce0cca00ef5cbe07453541"
 
 JSV@^4.0.x:
@@ -1062,11 +1074,23 @@ array-includes@^3.1.6:
     get-intrinsic "^1.1.3"
     is-string "^1.0.7"
 
+array-union@^1.0.1:
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/array-union/-/array-union-1.0.2.tgz#9a34410e4f4e3da23dea375be5be70f24778ec39"
+  integrity sha512-Dxr6QJj/RdU/hCaBjOfxW+q6lyuVE6JFWIrAUpuOOhoJJoQ99cUn3igRaHVB5P9WrgFVN0FfArM3x0cueOU8ng==
+  dependencies:
+    array-uniq "^1.0.1"
+
 array-union@^2.1.0:
   version "2.1.0"
   resolved "https://registry.yarnpkg.com/array-union/-/array-union-2.1.0.tgz#b798420adbeb1de828d84acd8a2e23d3efe85e8d"
   integrity sha512-HGyxoOTYUyCM6stUe6EJgnd4EoewAI7zMdfqO+kGjnlZmBDz/cR5pf8r/cR4Wq60sL/p0IkcjUEEPwS3GFrIyw==
 
+array-uniq@^1.0.1:
+  version "1.0.3"
+  resolved "https://registry.yarnpkg.com/array-uniq/-/array-uniq-1.0.3.tgz#af6ac877a25cc7f74e058894753858dfdb24fdb6"
+  integrity sha512-MNha4BWQ6JbwhFhj03YK552f7cb3AzoE8SzeljgChvL1dl3IcvggXVz1DilzySZkCja+CXuZbdW7yATchWn8/Q==
+
 array-unique@^0.2.1:
   version "0.2.1"
   resolved "https://registry.yarnpkg.com/array-unique/-/array-unique-0.2.1.tgz#a1d97ccafcbc2625cc70fadceb36a50c58b01a53"
@@ -2459,6 +2483,13 @@ clean-stack@^2.0.0:
   resolved "https://registry.yarnpkg.com/clean-stack/-/clean-stack-2.2.0.tgz#ee8472dbb129e727b31e8a10a427dee9dfe4008b"
   integrity sha512-4diC9HaTE+KRAMWhDhrGOECgWZxoevMc5TlkObMqNSsVU62PYzXZ/SMTjzyGAFF1YusgxGcSWTEXBhp0CPwQ1A==
 
+clean-webpack-plugin@^4.0.0:
+  version "4.0.0"
+  resolved "https://registry.yarnpkg.com/clean-webpack-plugin/-/clean-webpack-plugin-4.0.0.tgz#72947d4403d452f38ed61a9ff0ada8122aacd729"
+  integrity sha512-WuWE1nyTNAyW5T7oNyys2EN0cfP2fdRxhxnIQWiAp0bMabPdHhoGxM8A6YL2GhqwgrPnnaemVE7nv5XJ2Fhh2w==
+  dependencies:
+    del "^4.1.1"
+
 cliui@^7.0.2:
   version "7.0.4"
   resolved "https://registry.yarnpkg.com/cliui/-/cliui-7.0.4.tgz#a0265ee655476fc807aea9df3df8df7783808b4f"
@@ -2487,7 +2518,6 @@ cls-bluebird@^2.1.0:
 
 "codemirror@git+https://github.com/hedgedoc/CodeMirror.git":
   version "5.65.9"
-  uid "951b3d94bb5ad9ac7b44642adbe595e843390506"
   resolved "git+https://github.com/hedgedoc/CodeMirror.git#951b3d94bb5ad9ac7b44642adbe595e843390506"
 
 collection-visit@^1.0.0:
@@ -3623,6 +3653,19 @@ define-property@^2.0.2:
     is-descriptor "^1.0.2"
     isobject "^3.0.1"
 
+del@^4.1.1:
+  version "4.1.1"
+  resolved "https://registry.yarnpkg.com/del/-/del-4.1.1.tgz#9e8f117222ea44a31ff3a156c049b99052a9f0b4"
+  integrity sha512-QwGuEUouP2kVwQenAsOof5Fv8K9t3D8Ca8NxcXKrIpEHjTXK5J2nXLdP+ALI1cgv8wj7KuwBhTwBkOZSJKM5XQ==
+  dependencies:
+    "@types/glob" "^7.1.1"
+    globby "^6.1.0"
+    is-path-cwd "^2.0.0"
+    is-path-in-cwd "^2.0.0"
+    p-map "^2.0.0"
+    pify "^4.0.1"
+    rimraf "^2.6.3"
+
 delaunator@5:
   version "5.0.0"
   resolved "https://registry.yarnpkg.com/delaunator/-/delaunator-5.0.0.tgz#60f052b28bd91c9b4566850ebf7756efe821d81b"
@@ -3695,7 +3738,6 @@ dezalgo@^1.0.4:
 
 "diff-match-patch@git+https://github.com/hackmdio/diff-match-patch.git":
   version "1.1.1"
-  uid c2f8fb9d69aa9490b764850aa86ba442c93ccf78
   resolved "git+https://github.com/hackmdio/diff-match-patch.git#c2f8fb9d69aa9490b764850aa86ba442c93ccf78"
 
 diff@5.0.0:
@@ -5132,7 +5174,7 @@ glob@7.2.0:
     once "^1.3.0"
     path-is-absolute "^1.0.0"
 
-glob@^7.1.2, glob@^7.1.3, glob@^7.1.4:
+glob@^7.0.3, glob@^7.1.2, glob@^7.1.3, glob@^7.1.4:
   version "7.2.3"
   resolved "https://registry.yarnpkg.com/glob/-/glob-7.2.3.tgz#b8df0fb802bbfa8e89bd1d938b4e16578ed44f2b"
   integrity sha512-nFR0zLpU2YCaRxwoCJvL6UvCH2JFyFVIvwTLsIf21AuHlMskA1hhTdk+LlYJtOlYt9v6dvszD2BGRqBL+iQK9Q==
@@ -5186,6 +5228,17 @@ globby@^11.0.1:
     merge2 "^1.4.1"
     slash "^3.0.0"
 
+globby@^6.1.0:
+  version "6.1.0"
+  resolved "https://registry.yarnpkg.com/globby/-/globby-6.1.0.tgz#f5a6d70e8395e21c858fb0489d64df02424d506c"
+  integrity sha512-KVbFv2TQtbzCoxAnfD6JcHZTYCzyliEaaeM/gH8qQdkKr5s0OP9scEgvdcngyk7AVdY6YVW/TJHd+lQ/Df3Daw==
+  dependencies:
+    array-union "^1.0.1"
+    glob "^7.0.3"
+    object-assign "^4.0.1"
+    pify "^2.0.0"
+    pinkie-promise "^2.0.0"
+
 gopd@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/gopd/-/gopd-1.0.1.tgz#29ff76de69dac7489b7c0918a5788e56477c332c"
@@ -5927,6 +5980,25 @@ is-number@^7.0.0:
   resolved "https://registry.yarnpkg.com/is-number/-/is-number-7.0.0.tgz#7535345b896734d5f80c4d06c50955527a14f12b"
   integrity sha512-41Cifkg6e8TylSpdtTpeLVMqvSBEVzTttHvERD741+pnZ8ANv0004MRL43QKPDlK9cGvNp6NZWZUBlbGXYxxng==
 
+is-path-cwd@^2.0.0:
+  version "2.2.0"
+  resolved "https://registry.yarnpkg.com/is-path-cwd/-/is-path-cwd-2.2.0.tgz#67d43b82664a7b5191fd9119127eb300048a9fdb"
+  integrity sha512-w942bTcih8fdJPJmQHFzkS76NEP8Kzzvmw92cXsazb8intwLqPibPPdXf4ANdKV3rYMuuQYGIWtvz9JilB3NFQ==
+
+is-path-in-cwd@^2.0.0:
+  version "2.1.0"
+  resolved "https://registry.yarnpkg.com/is-path-in-cwd/-/is-path-in-cwd-2.1.0.tgz#bfe2dca26c69f397265a4009963602935a053acb"
+  integrity sha512-rNocXHgipO+rvnP6dk3zI20RpOtrAM/kzbB258Uw5BWr3TpXi861yzjo16Dn4hUox07iw5AyeMLHWsujkjzvRQ==
+  dependencies:
+    is-path-inside "^2.1.0"
+
+is-path-inside@^2.1.0:
+  version "2.1.0"
+  resolved "https://registry.yarnpkg.com/is-path-inside/-/is-path-inside-2.1.0.tgz#7c9810587d659a40d27bcdb4d5616eab059494b2"
+  integrity sha512-wiyhTzfDWsvwAW53OBWF5zuvaOGlZ6PwYxAbPVDhpm+gM09xKQGjBq/8uYN12aDvMxnAnq3dxTyoSoRNmg5YFg==
+  dependencies:
+    path-is-inside "^1.0.2"
+
 is-path-inside@^3.0.3:
   version "3.0.3"
   resolved "https://registry.yarnpkg.com/is-path-inside/-/is-path-inside-3.0.3.tgz#d231362e53a07ff2b0e0ea7fed049161ffd16283"
@@ -6129,7 +6201,6 @@ js-sdsl@^4.1.4:
 
 "js-sequence-diagrams@git+https://github.com/hedgedoc/js-sequence-diagrams.git":
   version "2.0.1"
-  uid bda0e49b6c2754f3c7158b1dfb9ccf26efc24b39
   resolved "git+https://github.com/hedgedoc/js-sequence-diagrams.git#bda0e49b6c2754f3c7158b1dfb9ccf26efc24b39"
   dependencies:
     lodash "4.17.x"
@@ -6659,7 +6730,6 @@ lutim@^1.0.2:
 
 "lz-string@git+https://github.com/hackmdio/lz-string.git":
   version "1.4.4"
-  uid efd1f64676264d6d8871b01f4f375fc6ef4f9022
   resolved "git+https://github.com/hackmdio/lz-string.git#efd1f64676264d6d8871b01f4f375fc6ef4f9022"
 
 make-dir@^1.0.0:
@@ -6973,7 +7043,6 @@ mermaid@9.1.7:
 
 "meta-marked@git+https://github.com/hedgedoc/meta-marked":
   version "0.4.5"
-  uid "0cb5065253ab0f9851baec34dc9edbb40eabf3d0"
   resolved "git+https://github.com/hedgedoc/meta-marked#0cb5065253ab0f9851baec34dc9edbb40eabf3d0"
   dependencies:
     js-yaml "~4.1.0"
@@ -7790,7 +7859,7 @@ oauth@0.9.x:
   resolved "https://registry.yarnpkg.com/oauth/-/oauth-0.9.15.tgz#bd1fefaf686c96b75475aed5196412ff60cfb9c1"
   integrity sha512-a5ERWK1kh38ExDEfoO6qUHJb32rd7aYmPHuyCu3Fta/cnICvYmgd2uhuKXvPD+PXB+gCEYYEaQdIRAjCOwAKNA==
 
-object-assign@^4.1.0, object-assign@^4.1.1:
+object-assign@^4.0.1, object-assign@^4.1.0, object-assign@^4.1.1:
   version "4.1.1"
   resolved "https://registry.yarnpkg.com/object-assign/-/object-assign-4.1.1.tgz#2109adc7965887cfc05cbbd442cac8bfbb360863"
   integrity sha512-rJgTQnkUnH1sFw8yT6VSU3zD3sWmu6sZhIseY8VX+GRu3P6F7Fu+JNDoXfklElbLJSnc3FUQHVe4cU5hj+BcUg==
@@ -8000,6 +8069,11 @@ p-locate@^5.0.0:
   dependencies:
     p-limit "^3.0.2"
 
+p-map@^2.0.0:
+  version "2.1.0"
+  resolved "https://registry.yarnpkg.com/p-map/-/p-map-2.1.0.tgz#310928feef9c9ecc65b68b17693018a665cea175"
+  integrity sha512-y3b8Kpd8OAN444hxfBbFfj1FY/RjtTd8tzYwhUqNYXx0fXx2iX4maP4Qr6qhIKbQXI02wTLAda4fYUbDagTUFw==
+
 p-map@^4.0.0:
   version "4.0.0"
   resolved "https://registry.yarnpkg.com/p-map/-/p-map-4.0.0.tgz#bb2f95a5eda2ec168ec9274e06a747c3e2904d2b"
@@ -8261,6 +8335,11 @@ path-is-absolute@^1.0.0, path-is-absolute@^1.0.1:
   resolved "https://registry.yarnpkg.com/path-is-absolute/-/path-is-absolute-1.0.1.tgz#174b9268735534ffbc7ace6bf53a5a9e1b5c5f5f"
   integrity sha512-AVbw3UJ2e9bq64vSaS9Am0fje1Pa8pbGqTTsmXfaIiMpnr5DlDhfJOuLj9Sf95ZPVDAUerDfEk88MPmPe7UCQg==
 
+path-is-inside@^1.0.2:
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/path-is-inside/-/path-is-inside-1.0.2.tgz#365417dede44430d1c11af61027facf074bdfc53"
+  integrity sha512-DUWJr3+ULp4zXmol/SZkFf3JGsS9/SIv+Y3Rt93/UjPpDpklB5f1er4O3POIbUuUJ3FXgqte2Q7SrU6zAqwk8w==
+
 path-key@^3.1.0:
   version "3.1.1"
   resolved "https://registry.yarnpkg.com/path-key/-/path-key-3.1.1.tgz#581f6ade658cbba65a0d3380de7753295054f375"
@@ -8380,6 +8459,11 @@ picomatch@^2.0.4, picomatch@^2.2.1, picomatch@^2.3.1:
   resolved "https://registry.yarnpkg.com/picomatch/-/picomatch-2.3.1.tgz#3ba3833733646d9d3e4995946c1365a67fb07a42"
   integrity sha512-JU3teHTNjmE2VCGFzuY8EXzCDVwEqB2a8fsIvwaStHhAWJEeVd1o1QD80CU6+ZdEXXSLbSsuLwJjkCBWqRQUVA==
 
+pify@^2.0.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/pify/-/pify-2.3.0.tgz#ed141a6ac043a849ea588498e7dca8b15330e90c"
+  integrity sha512-udgsAY+fTnvv7kI7aaxbqwWNb0AHiB0qBO89PZKPkoTmGOgdbrHDKD+0B2X4uTfJ/FT1R09r9gTsjUjNJotuog==
+
 pify@^3.0.0:
   version "3.0.0"
   resolved "https://registry.yarnpkg.com/pify/-/pify-3.0.0.tgz#e5a4acd2c101fdf3d9a4d07f0dbc4db49dd28176"
@@ -8390,6 +8474,18 @@ pify@^4.0.1:
   resolved "https://registry.yarnpkg.com/pify/-/pify-4.0.1.tgz#4b2cd25c50d598735c50292224fd8c6df41e3231"
   integrity sha512-uB80kBFb/tfd68bVleG9T5GGsGPjJrLAUpR5PZIrhBnIaRTQRjqdJSsIKkOP6OAIFbj7GOrcudc5pNjZ+geV2g==
 
+pinkie-promise@^2.0.0:
+  version "2.0.1"
+  resolved "https://registry.yarnpkg.com/pinkie-promise/-/pinkie-promise-2.0.1.tgz#2135d6dfa7a358c069ac9b178776288228450ffa"
+  integrity sha512-0Gni6D4UcLTbv9c57DfxDGdr41XfgUjqWZu492f0cIGr16zDU06BWP/RAEvOuo7CQ0CNjHaLlM59YJJFm3NWlw==
+  dependencies:
+    pinkie "^2.0.0"
+
+pinkie@^2.0.0:
+  version "2.0.4"
+  resolved "https://registry.yarnpkg.com/pinkie/-/pinkie-2.0.4.tgz#72556b80cfa0d48a974e80e77248e80ed4f7f870"
+  integrity sha512-MnUuEycAemtSaeFSjXKW/aroV7akBbY+Sv+RkyqFjgAe73F+MR0TBWKBRDkmfWq/HiFmdavfZ1G7h4SPZXaCSg==
+
 pkg-dir@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/pkg-dir/-/pkg-dir-2.0.0.tgz#f6d5d1109e19d63edf428e0bd57e12777615334b"