Update Ruby version to 2.1.5.
Update Devise dependency and remove devise-encryptable dependency.
Remove mail_form dependency.
Update active_model_serializers dependency.
Update jquery-rails dependency.
Update dotenv and dotenv-rails dependency.
Update capybara dependency.
Update database_cleaner dependency.
Update factory_girl_rails dependency.
Update foreman dependency.
Update should-matchers dependency.
Update sqlite3 dependency.
Update timecop dependency.
Update pry-meta dependency.
Update byebug dependency.
Update better_errors dependency.
Update bullet dependency.
Update newrelic_rpm dependency.
Update responders dependency.
Update the Devise initializer based on the initializer boilerplate of the latest Devise.