OAuth2 Gmail

Added OAuth2 GMAIL loggin/logout support.
      Added OAuth2 Gmail filter.
LoginModule
      Updated LoginModule with OAuth2 Gmail support.
Persitence
      Extended user persitance api with OAuth2 gmail features.
      (TODO refactor persistance as an user extention)

src/persistence/user/cms_user_storage_null.e

@@ -107,4 +107,24 @@ feature -- Change: User password recovery
 			-- <Precursor>.
 		do
 		end
+
+feature -- Change User Oauth
+
+	new_user_oauth2_gmail (a_token: READABLE_STRING_32; a_user_profile: READABLE_STRING_32; a_user: CMS_USER)
+			-- Add a new user with oauth2 gmail authentication.
+		do
+		end
+
+	update_user_oauth2_gmail (a_token: READABLE_STRING_32; a_user_profile: READABLE_STRING_32; a_user: CMS_USER)
+			-- Update user `a_user' with oauth2 gmail authentication.
+		do
+		end
+
+	user_oauth2_gmail_by_id (a_uid: like {CMS_USER}.id): detachable CMS_USER
+		do
+		end
+
+	user_by_oauth2_gmail_token (a_token: READABLE_STRING_32): detachable CMS_USER
+		do
+		end
 end