redirect back to request after login

completes #94

test/controllers/admin/auth_controller_test.rb

@@ -26,6 +26,18 @@ module Admin
       assert_redirected_to admin_url
     end
 
+    test "should auth to original request" do
+      elsie = candidates(:elsie)
+
+      get admin_result_url(test_hash: elsie.test_hash)
+
+      assert_redirected_to admin_login_url
+      post admin_auth_url, params: { auth:
+          { email: 'fed.reviewer@mailinator.com', password: 'password' } }
+
+      assert_redirected_to admin_result_url(test_hash: elsie.test_hash)
+    end
+
     test "should FAIL auth" do
       post admin_auth_url, params: { auth:
           { email: 'alan.admin@mailinator.com', password: 'b@d9a$$werD' } }