Merge pull request #94 from michaelnamlee/r2d2

Groups - model implementation (p. 1)
Groups - model implementation (p. 2)
Groups (p. 3)
Resolving "Group" conflict
Merge branch 'r2d2' of https://github.com/robogals/myrobogals into r2d2-pw
added rg_message and rg_repo apps