en passant rule

app/src/main/java/chess/model/Move.java

@@ -3,10 +3,12 @@ package chess.model;
 public class Move {
 	private final Coordinate start;
 	private final Coordinate finish;
+	private Coordinate deadPieceCoords;
 
 	public Move(Coordinate start, Coordinate finish) {
 		this.start = start;
 		this.finish = finish;
+		this.deadPieceCoords = finish;
 	}
 
 	public boolean isValid() {
@@ -39,4 +41,16 @@ public class Move {
 		return 0;
 	}
 
+	public Coordinate getMiddle() {
+		return Coordinate.fromIndex((getStart().toIndex() + getFinish().toIndex()) / 2);
+	}
+
+	public void setDeadPieceCoords(Coordinate deadCoords) {
+		this.deadPieceCoords = deadCoords;
+	}
+
+	public Coordinate getDeadPieceCoords() {
+		return deadPieceCoords;
+	}
+
 }