When you create your first City in Dragons of Atlantis you will be presented with 10 starter Rubies to assist you. You can use these Rubies to purchase items in the Shop to help you progress in the game.
If you would like to acquire more Rubies, you can purchase them on Facebook, Google+
Purchases on Facebook must be made with Facebook Credits, so you will be given the chance to acquire these before receiving your Rubies.
Purchases on Google+ must be made with Google Play. If you do not already have an account it is possible to make one when you attempt to purchase Rubies.