Merge pull request #83 from joehybird/master

Fix unclosed file warning issue.

Author: hsmett

mail_factory/messages.py

@@ -46,7 +46,10 @@ def attach_related_file(self, path, mimetype=None, filename=None):
         """Attaches a file from the filesystem."""
         if not filename:
             filename = basename(path)
-        content = open(path, 'rb').read()
+
+        with open(path, 'rb') as fd:
+            content = fd.read()
+
         self.attach_related(filename, content, mimetype)
 
     def _create_message(self, msg):