Add Resource and its relationship model.
Add resource interface.
append link_id attributes when we create resource.
update.
binding requirement and future resources.
display image and embed video in edit.
comment, votable gem.
add js helper.
comment feature.
Merge branch 'feature/tr-OblxkRa4-11-resource-list' into develop
reply comment.
reply
add closure_tree to keep comment hierarchy.
Add Vote backend.
development mail host.
devise default view.
for current user.
like for comment feature.
Add simple sider.
We don't need to toggle sider menu, now.