Add formatter class

@variousred I like this idea but I'm not sure if it's going to work. Anything outside of def blocks get evaluated first...so in the below scenario, @services hasn't been set yet and blows up calling each on nil. Any ideas?

```Ruby
def initialize(client_urn, services)
  @client_urn = client_urn
  @services = [services].flatten
end

@services.each do |service|
  define_method("#{service}_app_name") do
    app_name_for(service)
  end

  define_method("#{service}_url") do
    "https://#{send(:"#{service}_app_name")}.herokuapp.com"
  end
end
```