Install pry
Fix 'require' error when running tests via guard
Remove obsolete RSpec config setting
Restore default time zone handling in Mongoid config
Display activities using browser's time zone

  - Install jstz (http://pellepim.bitbucket.org/jstz/)
  - Set time zone in a cookie
  - Use the time zone from the cookie as the time zone for the request
  - Update the feature specs that need to know the user's time zone

All activities are still stored in the database as UTC. And we want that
to continue to be the case. With this commit, we allow the data to be
*displayed* in a user-friendly time zone, without altering the way we
store the data, *and* without requiring the developer to customize the
Rails timezone in config/application.rb.
Use consistent quotes in Gemfile
Update dependencies