Create a function taking a positive integer as its parameter and returning a string containing the Roman Numeral representation of that integer.
Modern Roman numerals are written by expressing each digit separately starting with the left most digit and skipping any digit with a value of zero. In Roman numerals 1990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC. 2008 is written as 2000=MM, 8=VIII; or MMVIII. 1666 uses each Roman symbol in descending order: MDCLXVI.
Example:
conversion.solution(1000); //should return "M"
Help:
Symbol Value
I 1
V 5
X 10
L 50
C 100
D 500
M 1,000
Remember that there can't be more than 3 identical symbols in a row.
More about roman numerals - https://en.wikipedia.org/wiki/Roman_numerals