Add instagram background implementation and generalize application for other identity providers

spec/factories/user_factory.rb

@@ -2,5 +2,19 @@ FactoryGirl.define do
   factory :user do
     sequence( :email ){|i| "test#{i}@example.com" }
     password "secret"
+
+    trait :other_auth do
+     auth_data( {
+        'info' => {
+          'nickname' => "UOther",
+          "name" => "USR Other",
+          "first_name" => "Usother"
+        },
+        "credentials" => {
+          "token" => "fbAuthToken234",
+          'expires' => false
+        }
+      })
+    end
   end
 end