I try to integrate Fabric/Crashlytics via CocoaPods, my Podfile looks like this:
pod \'Fabric/Core\', \'1.2\'
pod \'Fabric/Crashlytics\', \'1.2\'
Typically I would recommend not going against the grain and using the Fabric App for installation. Its hands down the simplest integration tool I've ever seen given the complexity they are providing.
That being said, since you're dead set on using Cocoapods, the only way to get things going would be the following