feat: preview of next shape

src/main/java/eu/midnightdust/yaytris/game/TetrominoShape.java

@@ -41,8 +41,17 @@ public enum TetrominoShape {
 
     final int[][] boundary;
     final Color color;
+
     TetrominoShape(int[][] boundary, Color color) {
         this.boundary = boundary;
         this.color = color;
     }
+
+    public int[][] getBoundary() {
+        return boundary;
+    }
+
+    public Color getColor() {
+        return color;
+    }
 }