Added mongodb service to travis.
Added mongodb service to travis.

MansurAshraf/storehaus,nkhuyu/storehaus,AndreasPetter/storehaus,twitter/storehaus,twitter/storehaus,cevaris/storehaus,sdjamaa/storehaus,tresata/storehaus,nkhuyu/storehaus,joychugh/storehaus,joychugh/storehaus,tresata/storehaus,franklinhu/storehaus,rubanm/storehaus,franklinhu/storehaus,AndreasPetter/storehaus,rubanm/storehaus,MansurAshraf/storehaus,cevaris/storehaus,sdjamaa/storehaus