Getting 2 error alerts while trying to change description ("uknown error" & "GitHub returned error 401")

[eyalzek]

Creating Gists works great, opening and updating them works great.
When I try to change the description of a gist, I get these 2 alerts; first of all the "unknown error (please, report a bug!)" and underneath it, a second alert which says I have bad credentials.

This strikes me as weird, because my credentials are obviously fine if I'm able to do all other operations.

[eyalzek]

Well I looked into that and found the problem; on line 278 on gist.py, the new description was passed to update_gist without specifying the correct param name. changing the func invocation from:
new_gist = update_gist(gist_url, {}, description)
to this:
new_gist = update_gist(gist_url, {}, new_description=description)
fixed this problem...

Created a pull request:
#159

[condemil]

Thank you for your contribution!