docs(contributing): add contributing instructions
docs(contributing): add contributing instructions

ranstyr/whizzco,VictorPavlyuk/AngularJS,kuem2405/vmemo,sahil0026/pint,kuem2405/vmemo,jeffrychristian93/PJIDEMO,bajajpayal/ng2-admin,VictorPavlyuk/AngularJS,TrungVuDang/ng2-admin,eko-point/ng2-admin,TrungVuDang/ng2-admin,ramsunvtech/ng2-admin,TrungVuAnt/ng2-admin,ranstyr/whizzco,julien-noblet/calcoo,supun19/directPayFrontend,VictorPavlyuk/AngularJS,flxc4p4str/NYA_Portal,ranstyr/whizzco,jeffrychristian93/PJIDEMO,AlbertXingZhang/ng2-admin,VictorPavlyuk/AngularJS,sahil0026/pint,hcaceres0515/masinmobiliaria,kuem2405/vmemo,AlbertXingZhang/ng2-admin,hcaceres0515/masinmobiliaria,jeffrychristian93/PJIDEMO,ranstyr/whizzco,sahil0026/pint,sahil0026/pint,julien-noblet/calcoo,kuem2405/vmemo,supun19/directPayFrontend,AlbertXingZhang/ng2-admin,hcaceres0515/masinmobiliaria,TrungVuAnt/ng2-admin,ashikul/6sixer-analytics,hcaceres0515/masinmobiliaria,ashikul/6sixer-analytics,TrungVuAnt/ng2-admin,TrungVuDang/ng2-admin,bajajpayal/ng2-admin,bajajpayal/ng2-admin,flxc4p4str/NYA_Portal,ramsunvtech/ng2-admin,jeffrychristian93/PJIDEMO,eko-point/ng2-admin,AlbertXingZhang/ng2-admin,jskrnbindra/AMSsidebarExtract,julien-noblet/calcoo,AtouiIlyes/AngularBackend,supun19/directPayFrontend,ramsunvtech/ng2-admin,ashikul/6sixer-analytics,AtouiIlyes/AngularBackend,Enrika/angular2-test,TrungVuAnt/ng2-admin,eko-point/ng2-admin,jskrnbindra/AMSsidebarExtract,bajajpayal/ng2-admin,jskrnbindra/AMSsidebarExtract,Enrika/angular2-test,AtouiIlyes/AngularBackend,Enrika/angular2-test,julien-noblet/calcoo,TrungVuDang/ng2-admin,flxc4p4str/NYA_Portal,flxc4p4str/NYA_Portal,AlbertXingZhang/ng2-admin,Enrika/angular2-test,ramsunvtech/ng2-admin,ashikul/6sixer-analytics,eko-point/ng2-admin,supun19/directPayFrontend,AtouiIlyes/AngularBackend,jskrnbindra/AMSsidebarExtract