Rails 4 - Gem::LoadError: Specified 'mysql2' for database adapter, but the gem is not loaded

In my gemfile I have: gem 'mysql2' My database.yml is as follows: default: &default adapter: mysql2 database: <%= ENV['db_name'] %> username: <%= ENV['db_user'] %> password: <%= ENV['db_pass'] %> host: <%= ENV['db_host'] %> pool: 32 socket: <%= ENV['socket'] %> development: <<: *default production: <<: *default I've run both bundle update and bundle install and my Gemfile.lock shows mysql2. Howeve