Refactor server with Sequelize ORM, refactor server configs, now will show note status (created or updated) and support docs (note alias)

public/docs/yaml-metadata.md

@@ -0,0 +1,97 @@
+---
+robots: index, follow
+lang: en
+dir: ltr
+breaks: true
+---
+
+Supported YAML metadata
+===
+
+First you need to insert syntax like this at the **start** of the note:
+```
+---
+YAML metas
+---
+```
+
+Replace the "YAML metas" in this section with any YAML options as below.
+You can also refer to this note's source code.
+
+robots
+---
+This option will give below meta in the note head meta:
+```xml
+<meta name="robots" content="your_meta">
+```
+So you can prevent any search engine index your note by set `noindex, nofollow`.
+
+> default: not 
+
+**Example**
+```xml
+robots: noindex, nofollow
+```
+
+lang
+---
+This option will set the language of the note, that might alter some typography of it.
+You can find your the language code in ISO 639-1 standard:
+https://en.wikipedia.org/wiki/List_of_ISO_639-1_codes
+
+> default: not set (which will be en)
+
+**Example**
+```xml
+langs: ja-jp
+```
+
+dir
+---
+This option provide to describe the direction of the text in this note.
+You can only use whether `rtl` or `ltr`.
+Look more at here:
+http://www.w3.org/International/questions/qa-html-dir
+
+> default: not set (which will be ltr)
+
+**Example**
+```xml
+dir: rtl
+```
+
+breaks
+---
+This option means the hardbreaks in the note will be parsed or be ignore.
+The original markdown syntax breaks only if you put space twice, but HackMD choose to breaks every time you enter a break.
+You can only use whether `true` or `false`.
+
+> default: not set (which will be true)
+
+**Example**
+```xml
+breaks: false
+```
+
+mathjax
+---
+This option let you to choose to parse mathjax syntax or not.
+
+> default: not set (which will be true)
+
+**Example**
+```xml
+mathjax: false
+```
+
+spellcheck
+---
+**Warning: Experimental feature!**
+This option let you to choose to enable spell checking feature or not.
+
+> default: not set (which will be false)
+
+**Example**
+```xml
+spellcheck: true
+```