Create Groups/ Achievements

[realAndrewCohn]

Reposting from Slack:

Asserted by group Id
Which is passed in the req.quer

Look at old group class to get a feel
Idea is to make it as minimally invasive in the game code as possible
And need a new route and validation for group/:I'd to get their group info
So browser can display their achievements

[realAndrewCohn]

24 addressed part of this: creates endpoint for groups stats that serves JSON group data.

We still need:

• Achievements class
• Ability to calculate student achievements based on more than every 100 writes
• More interesting information about student errors