Add automatch capability

[amikula]

For doubles games, you have to wait for enough players to join and you also have to come up with a fair match. The automatch command takes care of both. By default, automatch will be on for 5 minutes, but users can specify an end time or a duration. See README.md for details.

[dblock]

First, great to see a complete feature PRed! Excited to get this merged.

The things I like is that it just automatically matches players. But I don't love the fact that it forces this to be a doubles game or that the language doesn't match challenge. What do you think of renaming automatch? Maybe play anyone in the next 10 minutes and play doubles in the next 10 minutes?

What do you think?

Plus:

• Fix the build, the spec failure looks legit.
• Squash your commits.

I'll make some comments inline.

[dblock]

Link the PR, like below.

[amikula]

Thanks for all the great comments! I'll work on it...really looking forward to getting this in.

Unfortunately, this past weekend when I loaded the code onto a different computer, I can't get the test suite to run successfully. Looks like DatabaseCleaner isn't working properly for some reason I can't ascertain. I guess that will have to be a different pull request once I get to the bottom of it. :-P

[dblock]

Happy to help! Post your detailed issues here.

[dblock]

Bump @amikula, I believe your DatabaseCleaner issue is fixed, they released a newer version that works with newer MongoDBs.