Unable to find a specification for ...

If anyone else is getting:

Unable to find a specification for … (libPusher in my case)

or the following:

Could not find cocoapods-0.19.1 in any of the sources

or even:

Pod::DSLError - Invalid Facebook-iOS-SDK.podspec file: undefined method `prepare_command=' for #

definitely try adding:

gem "cocoapods", '~> 0.23.0'

to your Gemfile, and then running:

pod setup && bundle update && bundle install

I guess there was a recent CocoaPods update that broke something with RubyMotion and motion-cocoapods.. or something.