sequelize should probably go in dependencies because it won't load without it:

```
Jons-MacBook-Pro:thimble.webmaker.org jon$ rm -rf node_modules/sequelize/
Jons-MacBook-Pro:thimble.webmaker.org jon$ node app.js

module.js:340
    throw err;
          ^
Error: Cannot find module 'sequelize'
    at Function.Module._resolveFilename (module.js:338:15)
    at Function.Module._load (module.js:280:25)
    at Module.require (module.js:364:17)
    at require (module.js:380:17)
    at module.exports (/Users/jon/Dropbox/Sites/thimble.webmaker.org/lib/database.js:2:19)
    at Object.<anonymous> (/Users/jon/Dropbox/Sites/thimble.webmaker.org/app.js:24:15)
    at Module._compile (module.js:456:26)
    at Object.Module._extensions..js (module.js:474:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
```