Add ldap callback definitions to initializer

app/controllers/omniauth_callbacks_controller.rb

@@ -32,10 +32,6 @@ class OmniauthCallbacksController < Devise::OmniauthCallbacksController
     end
   end
 
-  Gitlab.config.ldap.servers.each do |server|
-    alias_method server.provider_name, :ldap
-  end
-
   def omniauth_error
     @provider = params[:provider]
     @error = params[:error]

config/initializers/7_omniauth.rb

@@ -4,3 +4,9 @@ module OmniAuth::Strategies
     const_set(server.provider_class, Class.new(LDAP))
   end
 end
+
+OmniauthCallbacksController.class_eval do
+  Gitlab.config.ldap.servers.each do |server|
+    alias_method server.provider_name, :ldap
+  end
+end