fix(repository): Move backend code into subdirectory

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

backend/.eslintrc.js

@@ -0,0 +1,89 @@
+/* SPDX-FileCopyrightText: 2021 The HedgeDoc developers (see AUTHORS file)
+ *
+ *  SPDX-License-Identifier: CC0-1.0
+ */
+module.exports = {
+  parser: '@typescript-eslint/parser',
+  parserOptions: {
+    project: 'tsconfig.json',
+    sourceType: 'module',
+  },
+  overrides: [
+    {
+      files: ['test/**', 'src/**/*.spec.ts'],
+      extends: ['plugin:jest/recommended'],
+      rules: {
+        '@typescript-eslint/unbound-method': 'off',
+        '@typescript-eslint/no-unsafe-assignment': 'off',
+        '@typescript-eslint/no-unsafe-argument': 'off',
+        '@typescript-eslint/no-unsafe-member-access': 'off',
+        '@typescript-eslint/require-await': 'off',
+        '@typescript-eslint/explicit-function-return-type': 'off',
+        'jest/unbound-method': 'error',
+        'jest/expect-expect': [
+          'error',
+          {
+            assertFunctionNames: [
+              'expect',
+              'request.**.expect',
+              'agent[0-9]?.**.expect',
+            ],
+          },
+        ],
+        'jest/no-standalone-expect': [
+          'error',
+          {
+            additionalTestBlockFunctions: ['afterEach', 'beforeAll'],
+          },
+        ],
+      },
+    },
+  ],
+  plugins: ['@typescript-eslint', 'jest', 'eslint-plugin-local-rules'],
+  extends: [
+    'eslint:recommended',
+    'plugin:@typescript-eslint/recommended',
+    'plugin:@typescript-eslint/recommended-requiring-type-checking',
+    'plugin:prettier/recommended',
+  ],
+  root: true,
+  env: {
+    node: true,
+    jest: true,
+  },
+  rules: {
+    'local-rules/correct-logger-context': 'error',
+    'func-style': ['error', 'declaration'],
+    '@typescript-eslint/no-unused-vars': [
+      'warn',
+      { argsIgnorePattern: '^_+$' },
+    ],
+    '@typescript-eslint/explicit-function-return-type': 'warn',
+    'no-return-await': 'off',
+    '@typescript-eslint/return-await': ['error', 'always'],
+    '@typescript-eslint/naming-convention': [
+      'error',
+      {
+        selector: 'default',
+        format: ['camelCase'],
+        leadingUnderscore: 'allow',
+        trailingUnderscore: 'allow',
+      },
+      {
+        selector: 'enumMember',
+        format: ['UPPER_CASE'],
+      },
+      {
+        selector: 'variable',
+        format: ['camelCase', 'UPPER_CASE'],
+        leadingUnderscore: 'allow',
+        trailingUnderscore: 'allow',
+      },
+
+      {
+        selector: 'typeLike',
+        format: ['PascalCase'],
+      },
+    ],
+  },
+};