Restrict write access to whitelisted users.

Closes ndlib/planning#313
Merge branch 'master' into 313-restrict-to-whitelisted_users

* master: (21 commits)
  Bumping build identifier to "v2013.22"
  Changing pre-production application URL
  Bumping build identifier to "v2013.21"
  Removing staging Resque.inline
  Bumping build identifier to "v2013.20"
  Marking application_root_url as HTTPS
  Bumping build identifier to "v2013.19"
  Reworking maintenance script for VMs
  Adding helpful development gems
  Bumping build identifier to "v2013.18"
  Adding deploy maintanence option Fedora migration
  Adding logging to Migrator
  Adding VCR so specs pass
  Bumping build identifier to "v2013.17"
  Correcting start_masquerading_admin_accounts
  Bumping build identifier to "v2013.16"
  Explicitly requiring bootstrap/sass
  Bumping build identifier to "v2013.15"
  Updating bootstrap-sass
  Bumping build identifier to "v2013.14"
  ...
Updating schema.rb