init(node: Node, in context: Context) throws {
    id = node["id"]
    username = try node.extract("username")
    password = try node.extract("password")
    facebookID = try node.extract("facebook_id")
    googleID = try node.extract("google_id")
}

func makeNode(context: Context) throws -> Node {
    return try Node(node: [
        "id": id,
        "username": username,
        "password": password,
        "facebook_id": facebookID,
        "google_id": googleID,
        ])
}