Added group by support to Model
Added group by support to Model

jbroadway/elefant,twheel/elefant,jbroadway/elefant,AxorB/elefant,evan70/elefant,twheel/elefant,evan70/elefant,Open343/elefant,jbroadway/elefant,AxorB/elefant,R-J/elefant,R-J/elefant,Open343/elefant,jbroadway/elefant,R-J/elefant,twheel/elefant,Open343/elefant,evan70/elefant,AxorB/elefant