Add a method called GroupHeroes to the HeroesDB class. Declare your method in the HeroesDB.h file and define the method in the HeroesDB.cpp file. The method should add data to the $\_$groupedHeroes map field of the class. Make sure to make the keys case insensitive $($ignore the case$).$

The goal is to fill the $\_$groupedHeroes map where the keys are the first letters of the heroes and the value for each key is a vector of the heroes whose names start with that letter. EX: for the key $$B$,$ the value would contain a vector of all the heroes whose names start with B$.$

Loop over the heroes vector of the class.$$

Check if the first letter of each hero name is in the $\_$groupedHeroes map $($use the find method$).$

If the key is NOT found, then$$

create a new vector

add the hero to the vector

then add the vector to the map as the value for that initial letter.$$

If the letter is already in the map, then add the hero to the vector that is stored for that key.