TODO
----
* post filters
* fts
* projects
* readonly-db connection (using `PRAGMA query_only`)
* per-site public/ directories
* history (in `PostModel#update_post`)
* triggers for removing unused `post_tag` and `tag` entries
* configurable dashboard
  (like wordpress, choose modules, columns, layout)
* user password strength
* expires\_at for posts

* save and publish dropdown
* move slug to "advanced" in new blog
* make "new post" split button
* `post_changes` table
* `blog` `pages` and `projects` tables, and `post_type` column

Tabs
----
* Home
* Blog
* Pages
* Projects
* Users

Projects
--------
* webhook support: https://developer.github.com/v3/repos/hooks/#create-a-hook

Editors
-------
* tinymce (http://tinymce.com/)
* ckeditor!!                           <-- best
* ace (https://ace.c9.io/)             <-- best
* codemirror (http://codemirror.net/)