Mention apns_feedback in the readme [ci skip].
Move cert instructions to the wiki.
Fall back to ActiveSupport::Logger if ActiveSupport::BufferedLogger is not defined
Merge pull request #124 from wilg/master

Fall back to ActiveSupport::Logger for Rails 4.0.0.rc1 support
Decouple the storage backend.
Fix 2.0 failure.
Remove commented code.
Reflect on GCM canonical IDs. Fixes #123.
Initialize store in Rapns.push
time_to_live no longer requires collapse_key
Update changelog [ci skip].
3.3.0
Update readme [ci skip].