Add podspec to integrate with CocoaPods
user
```ruby
Pod::Spec.new do |s|

  s.name         = "Postino"
  s.version      = "0.0.1"
  s.summary      = ""
  s.homepage     = "https://github.com/miguelbassila/postino"
  s.license      = "MIT"
  s.author       = { "Miguel Bassila" => "miguelbassila@me.com" }
  s.source       = { :git => "https://github.com/miguelbassila/postino.git", :commit => "8502a848279893c8ef47bf851e9b6eb8fcea21de" }
  s.source_files  = "Postino/**/*.{h,m,swift}"

end
```
assistant