Use twitter.id_str instead of twitter.id because project.id is returned string explicitly by the following change

https://github.com/jaredhanson/passport-twitter/commit/d9112c4c0575c64243692a732c2590e8d158bdcf
Merge pull request #46 from memolog/fix-twitter-strategy

Use twitter.id_str instead of twitter.id in twitter strategy, great catch @memolog!