implement Piece constructor and getter

src/backend/Piece.java

@@ -1,21 +1,34 @@
 package backend;
 
 public class Piece {
+	
+	private int x;
+	private int y;
+	private PieceType type;
+	private boolean isWhite;
+	
+	public Piece(int x, int y, PieceType type,boolean isWhite) {
+		this.x = x;
+		this.y = y;
+		this.type = type;
+		this.isWhite = isWhite;
+	}
+	
 
 	public int getX() {
-		return 0;
+		return x;
 	}
 
 	public int getY() {
-		return 0;
+		return y;
 	}
 	
 	public PieceType getType() {
-		return null;
+		return type;
 	}
 	
 	public boolean isWhite() {
-		return false;
+		return isWhite;
 	}
 	
 }