// Responses to a registration request

// Default response: Only error codes.
{
  "errors": {
    "username": [
      "length",
      "trailing-underscore",
      "leading-underscare"
    ],
    "email": [
      "email"
    ],
    "asdf": [
      "invalid-field"
    ]
  }
}

// With debug on.
{
  "errors": {
    "username": {
      "length": "usernames must be at least 2 characters long",
      "trailing-underscore": "usernames may not end with underscore",
      "leading-undercsore": "usernames may not start with underscores"
    },
    "email": {
      "email": "email is not valid"
    },
    "asdf": {
      "invalid-field": "that field is invalid"
    }
  }
}