Add isMod field for users, fix username duplicate checking, handle mod d/c
Some documentation
Remove user isMod field, replace with mod field for each room
Add user connected field, reset socket on reconnect
Assign new mod if available
Use stricts
Maintain list of connected users, remove user connected field
Use lodash for random sampling
Remove irrelevant comment
Merge pull request #1 from metakirby5/mod-dc

Handle mod d/c