WIP: Sync settings from GitHub

[bkeepers]

This is a very early work in progress to support syncing settings from GitHub. I likely wont have time to work on this any time soon, but wanted to get a PR open with some hacking I did a few days ago.

• Add a read method to fetch current settings for each repository
• Since each GitHub API response returns a lot of other data, use octokit/routes to determine which values from the response should be saved in the config file
• Use probot-scheduler to poll for updated settings for each repository (since there are no webhooks fired for most settings changes)
• Open a Pull Request whenever settings have changed
• Open a Pull Request with initial values when the app is installed

Fixes #1
Fixes #41

[travi]

you've probably already considered this, but something to consider either way. what would be the flow for a repo that includes .github/settings.yml in the initial commit?

the flow i'm thinking about would look something like:

• create new repo (empty repo with no initial readme, etc)
• app gets installed automatically since i have it enabled for all repos
• initial commit pushed with .github/settings.yml included

would the initial values PR still get created and just need to be closed, or would it not be sent?

[stale]

Is this still relevant? If so, what is blocking it? Is there anything you can do to help move it forward?

[Logerfo]

Too bad this is stale. I'd start using the bot if it had this feature.