Given a non-negative integer n, write a function to_binary/ToBinary which returns that number in a binary format.
to_binary(1) /* should return 1 / to_binary(5) / should return 101 / to_binary(11) / should return 1011 */ Example:
toBinary(1) /* should return 1 / toBinary(5) / should return 101 / toBinary(11) / should return 1011 */