Remove some unneeded gems

Gemfile

@@ -55,7 +55,6 @@ end
 gem 'administrate'
 gem 'dragonfly'
 gem 'dragonfly-s3_data_store'
-gem 'exception_notification', :git => 'git://github.com/rails/exception_notification', :require => 'exception_notifier'
 gem 'haml'
 gem 'kaminari'
 gem 'monban'
@@ -63,7 +62,6 @@ gem 'monban-generators'
 gem 'pg'
 gem 'redcarpet'
 gem 'simple_form'
-gem 'skylight'
 gem 'slugtastic'
 gem 'squeel'
 gem 'unf'

Gemfile.lock

@@ -1,9 +1,3 @@
-GIT
-  remote: git://github.com/rails/exception_notification
-  revision: 192a49a02d63d28b23ed41cebadfedd490929cf1
-  specs:
-    exception_notification (1.0.0)
-
 GEM
   remote: http://rubygems.org/
   specs:
@@ -281,8 +275,6 @@ GEM
       json (~> 1.8)
       simplecov-html (~> 0.10.0)
     simplecov-html (0.10.0)
-    skylight (0.10.3)
-      activesupport (>= 3.0.0)
     slop (3.6.0)
     slugtastic (1.2.1)
     sprockets (3.5.2)
@@ -331,7 +323,6 @@ DEPENDENCIES
   dotenv-rails
   dragonfly
   dragonfly-s3_data_store
-  exception_notification!
   factory_girl_rails
   fivemat
   haml
@@ -357,7 +348,6 @@ DEPENDENCIES
   shoulda-matchers
   simple_form
   simplecov
-  skylight
   slugtastic
   squeel
   uglifier