Basic swap request form and routing.

Current bug where automated meal creation creates shifts with nil start_time's
and end_time's.
Create ref between swap requests and shifts.

Ignore start_time/end_time.
Relate swap requests to coop.
Creating a swap_request adds that request to coop.
Basic listing of swap requests.
Merge branch 'master' into swap-interface

Conflicts:
	db/schema.rb
Clarify swap_request form.
Merge branch 'master' into swap-interface

Conflicts:
	app/views/users/_my_shifts.html.erb
	app/views/users/show.html.erb
	db/schema.rb
Remove unnecessary migrations, shift has many swap requests.
Allow for swap requests to be resolved.
Major UI improvement for swapportunity listing.
Forgot to include js in last commit.
Merge pull request #21 from daf-/swap-interface

Swap interface