Fixes #12199 - rails 4 migration errors

There are actually two parts to the issue of not being able to migrate
with this branch. The first is
https://gist.github.com/eLobato/0f5db50b5c93cc6c277c and can be
temporarily fixed with rails/sass-rails#136 (comment) I am not sure of a
long term fix for that atm.

Once that is patched, this error
https://gist.github.com/johnpmitsch/96e5ba3629890931193a happens on a
migration. This will fix that error by changing the Migrator class
initializer arguments which have changed from rails 3 to rails 4

app/services/foreman/plugin.rb

@@ -218,7 +218,7 @@ def role(name, permissions)
     end
 
     def pending_migrations
-      migrations = ActiveRecord::Migrator.new(:up, ActiveRecord::Migrator.migrations_paths).pending_migrations
+      migrations = ActiveRecord::Migrator.new(:up, ActiveRecord::Migrator.migrations(ActiveRecord::Migrator.migrations_paths)).pending_migrations
       migrations.size > 0
     end