add test file and run some tests

[nelsonpecora]

• add label - single word
• add labels - multiple / string escaped
• remove label
• remove labels - multiple / string escaped
• toggle labels
• reassign user
• add to milestone

[nelsonpecora]

It's not working yet. There's some kind of auth issue with the github api. I'm going to try doing the api calls through octocat.rb.