Is it possible to keep the submodule?

Author: thirsch

.gitmodules

@@ -1,3 +1,7 @@
+[submodule "lib/vendor/swiftmailer"]
+	path = lib/vendor/swiftmailer
+	url = https://github.com/swiftmailer/swiftmailer.git
+	branch = 5.x
 [submodule "lib/plugins/sfDoctrinePlugin/lib/vendor/doctrine"]
 	path = lib/plugins/sfDoctrinePlugin/lib/vendor/doctrine
 	url = https://github.com/LExpress/doctrine1.git