API methods only accepts hash with symbol keys

[jylamont]

class User
   include Vero::DSL

   def track_event
      vero.events.track!({
        :event_name => "test_event", 
        :identity: => {:email => "james@getvero.com"}
      }) # Passes validation

      vero.events.track!({
        "event_name" => "test_event", 
        "identity" => {"email" => "james@getvero.com"}
      }) # Fails validation
   end
end