.Podfile

target 'iMessageDemo' do
   use_frameworks!
   workspace 'iMessageDemo.xcworkspace'
   xcodeproj 'iMessageDemo.xcodeproj'
end

target 'iMessageExtensionDemo' do
   use_frameworks!
   workspace 'iMessageDemo.xcworkspace'
   xcodeproj 'iMessageDemo.xcodeproj'
   pod 'SwiftMessages/AppExtension', :path => '../'
end