Error formatting

For invalid JSON or any other general errors, such a response will be returned:

JSON

400 Bad Request

{
    message: "Problems parsing JSON, or any another error message"
}

For failed validation:

JSON

422 Unprocessable Entity
{
    message: "Validation Failed",
    errors: {
        username: [
            'Username is required.',
            'Username must contain only word characters.'
        ],
        email: [
            'Email address is invalid.'
        ]
    }
}