* Added twitter bootstrap
* Added flat-ui pro (sass version) to vendor directory
  * Converted with the help of another gem - see README
* Updated simple_form to 3.1.0.rc1
* Switched `form_for` to `simple_form_for` (WIP)
minor changes
renamed day_unit to activity
Ability to browse school days

* Introduced /days/:number routes
* Side nav with calendar when visiting above url
* Switched from number based counting of days to w2d4 and w2e (weekend)
style counting

Todo:
* tests
* migrate day from integer to string for activities
Added basic activities

* Modified seeds.rb to require ignored activities_seed.rb file
* Lectures for week1 added to (ignored) activities_seed.rb
* Added type column (STI) to Activity model (introduced first subclass:
Lecture)
activity seeder started (WIP)

* Broke out course calendar controller/view helpers into a concern
(used by 2 controllers now)
* Creating an activity with a gist URL now fetches the README.md and
saves it in the activity’s instruction field
days controller (missed in last commit)
fix to URLs in left nav calendar
fix test

activity factory update
fix activity importer

the gist ID was hardcoded - oops