Handle user creation if email is not provided

This fixes #1541

lib/gitlab/oauth/user.rb

@@ -73,6 +73,7 @@ module Gitlab
         end
 
         def email
+          return unless auth.info.respond_to?(:email)
           auth.info.email.downcase unless auth.info.email.nil?
         end
 

spec/lib/gitlab/oauth/user_spec.rb

@@ -41,5 +41,17 @@ describe Gitlab::OAuth::User do
       user.projects_limit.should == Gitlab.config.gitlab.default_projects_limit
       user.can_create_group.should == Gitlab.config.gitlab.default_can_create_group
     end
+
+    it "Set a temp email address if not provided (like twitter does)" do
+      info = double(
+        uid: 'my-uid',
+        nickname: 'john',
+        name: 'John'
+      )
+      auth = double(info: info, provider: 'my-provider')
+
+      user = gl_auth.create(auth)
+      expect(user.email).to_not be_empty
+    end
   end
 end