chore(Travis): Configure firefox for tests
chore(Travis): Configure firefox for tests

mabdelfattah/activeadmin_addons,mabdelfattah/activeadmin_addons,platanus/activeadmin_addons,halilim/activeadmin_addons,mabdelfattah/activeadmin_addons,siutin/activeadmin_addons,siutin/activeadmin_addons,platanus/activeadmin_addons,platanus/activeadmin_addons,mabdelfattah/activeadmin_addons,platanus/activeadmin_addons,halilim/activeadmin_addons,halilim/activeadmin_addons,siutin/activeadmin_addons