fix mass-assignment error in user create API

lib/api/users.rb

@@ -40,7 +40,7 @@ module Gitlab
       post do
         authenticated_as_admin!
         attrs = attributes_for_keys [:email, :name, :password, :password_confirmation, :skype, :linkedin, :twitter, :projects_limit]
-        user = User.new attrs
+        user = User.new attrs, as: :admin
         if user.save
           present user, with: Entities::User
         else

spec/requests/api/users_spec.rb

@@ -43,7 +43,7 @@ describe Gitlab::API do
 
     it "should create user" do
       expect {
-        post api("/users", admin), Factory.attributes(:user)
+        post api("/users", admin), Factory.attributes(:user, projects_limit: 3)
       }.to change { User.count }.by(1)
     end