Added Gitter badge to the README to direct users to the group.
Added Gitter badge to the README to direct users to the group.

Noobish1/Alamofire,iosheadhunter/Alamofire,Lomotif/Alamofire,Noobish1/Alamofire,easyui/Alamofire,Farteen/Alamofire,easyui/Alamofire,yimajo/Alamofire,Lomotif/Alamofire,richardPFisk/Alamofire,Farteen/Alamofire,jschmid/Alamofire,antigp/Alamofire,iosheadhunter/Alamofire,richardPFisk/Alamofire,jschmid/Alamofire,Alamofire/Alamofire,yimajo/Alamofire,antigp/Alamofire,Alamofire/Alamofire