add another sphere

src/main/java/eu/jonahbauer/raytracing/Main.java

@@ -10,7 +10,10 @@ import java.nio.file.Path;
 
 public class Main {
     public static void main(String[] args) throws IOException {
-        var scene = new Scene(new Sphere(0, 0, 1, 0.5));
+        var scene = new Scene(
+                new Sphere(0, 0, 1, 0.5),
+                new Sphere(0, -100.5, 1, 100)
+        );
         var camera = new Camera(256, 2, 16 / 9d);
 
         var image = scene.render(camera);