input: Write a python function to convert a string to Pig Latin.
  assert toPigLatin("hello") == "ellohay"
  assert toPigLatin("apple") == "appleway"
  assert toPigLatin("string") == "tringsay"
output: def toPigLatin(word):
      vowels = "aeiou"
      if word[0] in vowels:
          return word + "way"
      else:
          return word[1:] + word[0] + "ay"