What is CocoaPods?
"CocoaPods manages library dependencies for your Xcode projects.
The dependencies for your projects are specified in a single text file called a Podfile. CocoaPods will resolve dependencies between libraries, fetch the resulting source code, then link it together in an Xcode workspace to build your project.
Ultimately the goal is to improve discoverability of, and engagement in, third party open-source libraries by creating a more centralised ecosystem."
Installing cocoa pods
In terminal use the following two commands:
sudo gem install cocoapods
If you're using El Capitan and experiencing issues try this:
sudo gem install -n /usr/local/bin cocoapods