Write a function to_pig_latin that converts a word into pig latin, by:

1. Removing the first character from the start of the string,
2. Adding the first character to the end of the string,
3. Adding "ay" to the end of the string.

So, for example, this function converts "hello" to "ellohay". Unit test the function.

You can assume that the strings will always be at least two letters long.

Note: Technically, this isn’t real pig latin, since it doesn’t handle vowels correctly. We’ll learn how to do real pig-latin in a later lesson.