Write a function called double_list that accepts a list of strings as a parameter and returns a new list that replaces every string with two of that same string. For example, if the list has the values ['how', 'are', 'you?'], the function should return the list with the values ['how', 'how', 'are', 'are', 'you?', 'you?'].
original list: ['how', 'are', 'you?']
double list: ['how', 'how', 'are', 'are', 'you?', 'you?']