Make on_branch method backwards compatible
Add Repository#last_completed_build(branc)
Implement simple states cache at StatesCache

StatesCache caches the status for given repository and given branch.
It's purpose is to allow easily store information needed to quickly get
state for given repo and branch, for example in order to generate status
images.
Add StatesCache addon
Use states_cache in StatusImage
Change format for memcached options for states_cache
Set default memcached server to localhost
Add feature flip over states_cache
Merge pull request #204 from travis-ci/ps-states-cache

States cache
Treat array as HipChat config nicer.

It barfed when determining the message format, when the HipChat
configuration is just a list of rooms.
dump schema
calling find_admin without a repo now raises AdminMissing, too, see travis-ci/travis-ci#1045
raise RepositoryMissing instead of AdminMissing if there is no repo for the find_admin service
Merge pull request #208 from travis-ci/rkh-fix-find-admin

Check to make sure we have a repository in the find_admin service
Add support for channel keys.
Rename key to channel_key.
reduce Sidekiq retries to 8 total

the last retry happening 2 hours after the first
gracefully handle AR::SubclassNotFound in find_job

retrieving a Job with an old type subclass should return a RecordNotFound in find_job. eg. we don't support the Configure class anymore so we should handle this case gracefully
Don't check for last_build_started_at when getting for repos with builds

When we get repos for recent repos sidebar, we want only repos with
either started or finished builds. It looks differently on 'my
repositories' tab or when you search for repos. We should not display
repos without any builds there, because that most of the time means that
they're not configured, but we should not ommit a repo only because its
last build is queued.
Merge pull request #209 from travis-ci/mm-irc-channel-key

Add support for channel keys