pod install Pull is not possible because you have unmerged files.

http://stackoverflow.com/questions/21474536/podfile-gives-an-error-on-install

A bug was found in libgit2 and they had to execute a force push on the specs repo. This is what broke everyone's CocoaPods setup.

You can find the official post about this issue on the CocoaPods blog :http://blog.cocoapods.org/Repairing-Our-Broken-Specs-Repository/

The recommended way to fix your setup is to execute the following commands :

$ pod repo remove master
$ pod setup

If that doesn't work, you can also delete manually all your cached specs :

$ rm -rf ~/.cocoapods/
$ pod setup