support github enterprise

where `SECRETHOSTNAME` should be a variable or something.

```
   def initialize(user, pass, repo)
     @user = user
     $logger.debug("#{@user} connects to github repo '#{repo}'")
+    Octokit.configure do |c|
+      c.api_endpoint = "https://SECRETHOSTNAME/api/v3/"
+    end
```

details: https://github.com/octokit/octokit.rb#working-with-github-enterprise
