Allow format strings in a message

docs/config.rst

@@ -15,6 +15,15 @@ All settings are stored in :file:`settings.py` (as usual for Django).
 
     Message used on each commit Weblate does.
 
+    You can use following format strings in the message:
+
+    ``%(language)s``
+        Language code
+    ``%(subproject)s``
+        Subproject name
+    ``%(project)s``
+        Project name
+
 .. envvar:: ENABLE_HOOKS
 
     Whether to enable anonymous remote hooks.

weblate/trans/models.py

@@ -801,10 +801,15 @@ class Translation(models.Model):
         '''
         Commits translation to git.
         '''
+        msg = settings.COMMIT_MESSAGE % {
+            'language': self.language.code,
+            'subproject': self.subproject.name,
+            'project': self.subproject.project.name,
+        }
         gitrepo.git.commit(
             self.filename,
             author = author.encode('utf-8'),
-            m = settings.COMMIT_MESSAGE
+            m = msg
             )
         if sync:
             self.store_hash()