implemented to String method

src/cards/Suit.java

@@ -28,7 +28,21 @@ public enum Suit {
      */
     @Override
     public String toString() {
-        //TODO implement
-        return super.toString();
+        switch (this) {
+            case HEARTS:
+                return "♥";
+            
+            case DIAMONDS:
+                return "♦";
+
+            case CLUBS:
+                return "♣";
+
+            case SPADES:
+                return "♠";
+        
+            default:
+                return "";
+        }
     }
 }