Real Time Bus Tracker

The goal of this exercise is to fetch data from an API and use it to animate a map.
I implemented a function to update MBTA Route 1 buses geolocation in real time every 15 seconds, and I attached to them their own markers with the bus number to identify them. I added the buses' geolocation to an array and create markers with their positions. I also wrote a function to get rid of previous markers.