Refactors js files to coffeescript.

Since I made the switch to HALM in this project I figured I may as well
use coffeescript as well and for similar reasons: less code noise and
more elegant code.
Associations and database tune up.

Adds proper foreign keys and adjusts the has_many :dependent => :foo
declarations accordingly. Things are fairly standard here except
perhaps in the case of the FKs and :dependent option on the Ticket
model vis-a-vis Attachments and Comments. In those cases the FK is set
to the default of DELETE RESTRICT instead of CASCADE DELETE. I think it
is nicer to have the parent model manage its children directly as it makes
it more obvious what happens after deleting a parent record when looking
at the code. The FK setting here just ensures that you can't accidentally
shoot yourself in the foot down the line when writing rake tasks or doing
things in a willy-nilly manner on the command line in regards to child
record deletions.
Adds basic styling for tickets#index.

First stab at non-scaffolded UI for this app. Bootstrap is doing the
heavy lifting so far. Next view to get some UI treatment is tickets#new.