fix: debug refuel method in GasCar class

src/main/java/org/model/GasCar.java

@@ -37,7 +37,9 @@ public class GasCar extends Car implements Refuelable {
     // TODO: Implement refuel(double amount)
     @Override
     public void refuel(double amount) {
-        fuelLevel = 100;
+        if(fuelLevel + amount <= 100){
+            fuelLevel += amount;
+        }
     }