Add CommitsController spec to make sure atom feeds work

spec/controllers/commits_controller_spec.rb

+require 'spec_helper'
+
+describe CommitsController do
+  let(:project) { create(:project) }
+  let(:user)    { create(:user) }
+
+  before do
+    sign_in(user)
+
+    project.add_access(user, :read, :admin)
+  end
+
+  describe "GET show" do
+    context "as atom feed" do
+      it "should render as atom" do
+        get :show, project_id: project.code, id: "master.atom"
+        response.should be_success
+        response.content_type.should == 'application/atom+xml'
+      end
+    end
+  end
+end