split app into /api (rails) and /frontend (ember)

[hauntedhost]

how to get started:

$ git checkout ember-cli
$ cd rails && rake db:create && rake db:migrate && rake db:seed && rails s
# in another terminal
$ cd ember && ember install && ember serve --proxy http://localhost:3000
$ open http://localhost:4200/boards/4

current todo:

• rearranging lists
• sorting cards within list
• dragging cards between populated lists
• dragging card to empty list, bug: generates duplicate card 😡

[romankuznietsov]

The problem with card duplication occurred because both sortable and ember were inserting a new node.
Ember did not detect the presence of the card in the list when the list was empty.
One way to fix this is to delete the node inserted by sortable right before we push updates to the ember store.
You should also use sortable's 'stop' callback instead of 'update'. This callback will be called only once when dragging cards across lists and so will eliminate duplicate api requests.