This function should take in a string and a number as parameters and 'rotate' the string to the equivalent alphabet letter that is located at the letter position + 'rotation' parameter.

E.g.: `"stackoverflow" --- "fgnpxbiresybj"`

```
def caesar(inputString, rotation = 1):
    zNum = ord('z')
    alphaLen = 26

    result = []
    for c in inputString:
        charNum = ord(c) + rotation
        if charNum > zNum:
            result.append(chr(charNum - alphaLen))
        else:
            result.append(chr(charNum))

    return ''.join(result)