Added possibility to change player from human to ghost

src/main/java/ch/unibas/dmi/dbis/cs108/gamelogic/GhostifyHandler.java

@@ -0,0 +1,14 @@
+package ch.unibas.dmi.dbis.cs108.gamelogic;
+
+import ch.unibas.dmi.dbis.cs108.gamelogic.klassenstruktur.Passenger;
+
+public class GhostifyHandler {
+    /**
+     * Changes passenger at position x to ghost
+     * @param p
+     * Passenger to be ghostified
+     */
+    public void ghostify(Passenger p) {
+        p.setGhost();
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/gamelogic/klassenstruktur/Passenger.java

@@ -52,6 +52,11 @@ public class Passenger {
     this.kickedOff = kickedOff;
   }
 
+  public void setGhost() {
+    // changes this passenger's status from human to ghost
+    isGhost = true;
+  }
+
   public int getPosition() {
     return position;
   }