Less generators with rails_admin gem

If you have a Rails application that has rails_admin and you want to use less as the default generator for stylesheet, you'll need to add this hack since railsadmin forces you're app to use scss, even if you have ```config.appgenerators.stylesheet_engine :lessdeclared in yourconfig/application.rb```

module Less
 module Rails
 class Railtie
 initializer 'less-rails.force-set-stylesheet_engine.after-setup_sass', after: :setup_sass, group: :all do |app|
 config.app_generators.stylesheet_engine :less
 end
 end
 end
end