fix indent
define User#stocks with relation between User and Item
change share/follow.js to share/action.js for multi purpose uses
add stocking
fix views and controllers for changes on share/action
define followings and followers with has_and_belongs_to_many macro
fix tags#follow with User#follow_tag
describe User#followings and User#followers
describe User's indexes for followings and followers
implements User indexes as described
add users#stocks controller, routing, view
Merge branch 'add-stocks'

Add stacks feature like Qiita