fix(insert): add missing insert entry to interface

Fixes #542

Signed-off-by: Tobias Gurtzick <magic@wizardtales.com>

Author: wzrdtales

lib/interface/migratorInterface.js

@@ -114,7 +114,9 @@ MigratorInterface.prototype = {
 
   all: dummy,
 
-  close: dummy
+  close: dummy,
+
+  insert: dummy
 };
 
 module.exports = MigratorInterface;