updated contributors list in README
updated contributors list in README

Guestfolio/formtastic,Guestfolio/formtastic,ConferenceCloud/formtastic,sideci-sample/sideci-sample-formtastic,Davidzhu001/formtastic,thenthen8515/formtastic,thenthen8515/formtastic,pcreux/formtastic,mikz/formtastic,mikz/formtastic,Davidzhu001/formtastic,paulodiovani/formtastic,ryanfox1985/formtastic,justinfrench/formtastic,nishaya/formtastic,nishaya/formtastic,Baltazore/formtastic,justinfrench/formtastic,EndingChaung/formtastic,ConferenceCloud/formtastic,paulodiovani/formtastic,crashlytics/formtastic,justinfrench/formtastic,wested/formtastic,EndingChaung/formtastic,ryanfox1985/formtastic,pat/formtastic,ryanfox1985/formtastic