Added Travis status to README
Added Travis status to README

rjordan/activeresource,maclover7/activeresource,Shopify/activeresource,repinel/activeresource,chadzilla2080/activeresource,wyattisimo/activeresource,1776/activeresource,eileencodes/activeresource,om-nishu-trantor/activeresource,yui-knk/activeresource,rails/activeresource,SweeD/activeresource,delameko/activeresource,peterjm/activeresource