changed visibility for overloaded put-method in connect4

src/main/java/inf101/v20/sem2/mnkgames/ConnectFour.java

@@ -21,7 +21,7 @@ public class ConnectFour extends MNKGame{
 	 * 
 	 * @param x the column to which the piece is added  
 	 */
-	public void putPieceAt(int x) {
+	private void putPieceAt(int x) {
 		assert x >= 0 && x < getWidth();
 		
 		int firstAvailableRow = -1;