Process New Commits

[Gene Chudny]

When new commits are pushed, a PushEvent is generated with a list of commits.
Currently the commits are not queued which results in missing commits:

  PushEvent(request) {
    let [document] = this._addEventBasics(request);
    // TODO figure out what to do with the commits
    return document;
  }

See update_events function for implementation details.

[Gene Chudny]

Resolved by #91