title: Sails.js E_VALIDATION error
body: <p>I'm starting in sails.js by following a tuto and the sails.js doc .
  I'm creating a user account system, when I try to create a new user thru de user form a get this error :</p>
  
  <pre><code>{
    "error": "E_VALIDATION",
    "status": 400,
    "summary": "1 attribute is invalid",
    "model": "User",
    "invalidAttributes": {
      "hashedPassword": [
        {
          "rule": "string",
          "message": "`undefined` should be a string (instead of \"null\", which is a object)"
        },
        {
          "rule": "required",
          "message": "\"required\" validation rule failed for input: null"
        }
      ]
    }
  }
  </code></pre>
  
  <p>You can see my model below :</p>
  
  <pre><code>module.exports = {
  
    attributes: {
      name: { type: 'string', required: true },
      username: { type: 'string', required: true },
      email: { type: 'string', lowercase: true, email: true, required: true, unique: true },
      role: { type: 'string', default: 'user' },
      hashedPassword: { type: 'string', required: true },
      provider: 'string',
      salt: 'string',
      facebook: {},
      twitter: {},
      google: {},
      github: {}
    }
  };
  </code></pre>
  
  <p>And my controller:</p>
  
  <pre><code>module.exports = {
  
    'new': function(req, res){
      res.view();
    },
  
    'create': function(req, res, next){
      User.create(req.params.all(), function userCreated(err, user) {
        if (err) return next(err);
  
        res.json(user);
      });
    }
  };
  </code></pre>
  
  <p>Any help please ? thanks</p>