battlearray_client/Assets/Editor/Inspector/DoorInspector.cs

using UnityEditor;
using UnityEngine;
using System.Collections;

[CustomEditor(typeof(Door))]
public class DoorInspector : Editor {

	public override void OnInspectorGUI () {  

		DrawDefaultInspector();

		Door door = target as Door;
		door.occupyPriority = EditorGUILayout.IntField("Occupy Priority", door.occupyPriority);

	}
}