Update course.yml

Conflicts:
	_data/course.yml

Closes pull request #63

_data/course.yml

@@ -123,3 +123,7 @@ signups:
    image: https://avatars1.githubusercontent.com/u/10352010?v=3&u=1a5e67e72b5e2ae0518fd6fe0b16f3e7a1cf64de&s=140
    twitter: Clarissamfb
    github_username: clarissabezerra
+ - name: M C Morgan
+   image: http://www.gravatar.com/avatar/55f1d1ffbca0d409d46c48ffe5b08fb5.png
+   twitter: mcmorgan
+   github: mcmorgan53