Added Promotion resource with List and Get. Updated version to 0.0.4.

Author: Juan Rossi

README.md

@@ -72,3 +72,4 @@ These are the operations available for each resource:
 |Installments  | x |   |   |   |   |   |
 |Queue         | x | x | x |   | x | x |
 |Refunds       | x | x | x |   |   |   |
+|Promotions    | x |   | x |   |   |   |

lib/mango/resources.rb

@@ -34,4 +34,8 @@ class Installments < Resource
     public_class_method :list
   end
 
+  class Promotions < Resource
+    public_class_method :retrieve, :list
+  end
+
 end

mango-ruby.gemspec

@@ -2,7 +2,7 @@
 
 Gem::Specification.new do |s|
   s.name              = "mango-ruby"
-  s.version           = "0.0.3"
+  s.version           = "0.0.4"
   s.summary           = "Ruby wrapper for Mango API"
   s.description       = "API to interact with Mango\nhttps://getmango.com/"
   s.authors           = ["Mango development team", "Joaquín Vicente"]