title: How to create a map instance variable
body: <p>I've been trying to create a class that will model a scenario I've come up with. It will involve a map with string keys and values. </p>
  
  <p>I need to create an instance variable used to reference the map object, and a constructor that creates the empty map and assigns it to the map instance variable.</p>
  
  <p>I've been messing around with map objects but not creating a class using them, and I've hit a mental block!</p>
  
  <p>What's the proper way to actually get a map object?</p>