Rails 4 update.

Gemfile

@@ -1,33 +1,27 @@
 # -*- mode: yaml; -*-
 source 'http://rubygems.org'
 
-gem 'rails', '3.2.12'
+gem 'rails', '4.0.1'
 
 gem 'pg'
 
-gem 'bootstrap-sass', '2.0.2'
+gem 'bootstrap-sass', '~> 3.0.0.0'
 
 # Bourbon: fancy css mixins – https://github.com/thoughtbot/bourbon
-gem 'bourbon', '1.4.0'
-
-gem 'activeadmin', '0.4.0'
+gem 'bourbon'
 
 # https://github.com/plataformatec/devise
-gem 'devise', '2.0.4'
-gem 'bcrypt-ruby', '3.0.1'
+gem 'devise'
+gem 'bcrypt-ruby'
 
 # https://github.com/ryanb/cancan
-gem 'cancan', '1.6.5'
+gem 'cancan'
 
 # Deploy with Capistrano
-gem 'capistrano', '2.5.21'
+gem 'capistrano'
 
 # For avatar images: https://github.com/jnicklas/carrierwave
-# gem 'rmagick', '2.9.2'
-gem 'carrierwave', '0.6.2'
-
-# Specify this directly in order to use version we also have @production site. Otherwise, 'rdoc' pulls newest version in.
-gem 'json', '1.6.5'
+gem 'carrierwave'
 
 # We are sending mail. The latest version is just fine.
 gem 'mail'
@@ -42,15 +36,12 @@ gem 'mail'
 # gem 'sqlite3-ruby', :require => 'sqlite3'
 # gem 'aws-s3', :require => 'aws/s3'
 
-# Gems used only for assets and not required
-# in production environments by default.
-group :assets do
-  gem 'sass-rails', '3.2.5'
-  gem 'coffee-rails', '3.2.2'
-  gem 'uglifier'
-end
+# These used to be in an ":assets" group. Which has been removed by Rails 4.
+gem 'sass-rails'
+gem 'coffee-rails'
+gem 'uglifier'
 
-# gem 'jquery-rails'
+gem 'jquery-rails'
 
 # Bundle gems for the local environment. Make sure to
 # put test-only gems in this group so their generators