Fixed datetime to commit date formatting.

JNRowe · JNRowe · commit 0173a4992315 · 2011-05-22T10:19:00.000+01:00
Dates can now roundtrip.
diff --git a/github2/core.py b/github2/core.py
@@ -6,6 +6,7 @@
 GITHUB_DATE_FORMAT = "%Y/%m/%d %H:%M:%S"
 #2009-03-21T18:01:48-07:00
 COMMIT_DATE_FORMAT = "%Y-%m-%dT%H:%M:%S"
+COMMIT_TIMEZONE = "-07:00"
 
 
 def strptime(string, format):
@@ -55,7 +56,7 @@ def datetime_to_commitdate(datetime_):
     :param str datetime_: datetime object to convert
     """
     date_without_tz = datetime_.strftime(COMMIT_DATE_FORMAT)
-    return "".join([date_without_tz, GITHUB_TIMEZONE])
+    return "".join([date_without_tz, COMMIT_TIMEZONE])
 
 
 class GithubCommand(object):
