Run rails upgrade task

next bundle exec rails app:update

config/environment.rb

@@ -1,25 +1,5 @@
-# Load the rails application
-require File.expand_path('../application', __FILE__)
+# Load the Rails application.
+require_relative 'application'
 
-# Load the configuration file
-path = Rails.root.join('config', 'config.yml')
-if File.exist?(path)
-  puts "
-
-WARNING: The OSEM configuration file
-
-#{path}
-
-is deprecated. Please use the environment variables
-explained in INSTALL.md instead.
-
-There is a rake task to migrate your settings. For instance
-to migrate your settings for production:
-
-bundle exec rake data:migrate:config2dotenv RAILS_ENV=production
-
-"
-end
-
-# Initialize the rails application
-Osem::Application.initialize!
+# Initialize the Rails application.
+Rails.application.initialize!