gameexplorer: points cant be less than zero

src/main/java/de/tims/gameexplorer/Player.java

@@ -9,7 +9,7 @@ public class Player {
 	}
 
 	public void addPoints(int pointsToAdd) {
-		this.points += pointsToAdd;
+		this.points = (this.points + pointsToAdd > 0) ? this.points + pointsToAdd : 0;
 	}
 
 	public int getPoints() {

src/test/java/de/tims/gameexplorer/PlayerTest.java

@@ -25,7 +25,8 @@ class PlayerTest {
 		return Stream.of(Arguments.of("NoPointsBeforeGet0Points", 0, 0, 0),
 				Arguments.of("NoPointsBeforeGet10Points", 0, 10, 10),
 				Arguments.of("10PointsBeforeAdd10Points", 10, 10, 20),
-				Arguments.of("10PointsBeforeLose10Points", 10, -10, 0));
+				Arguments.of("10PointsBeforeLose10Points", 10, -10, 0),
+				Arguments.of("LoseMorePointsThanYouHave", 10, -20, 0));
 	}
 
 }