整理EntityDatabase代码

Assets/Scripts/EntityType.cs

@@ -2,8 +2,7 @@ namespace ECSTest
 {
     public enum EntityType
     {
-        Unit,
-        Monster,
+        Cannon,
         Bullet,
     }
 

Assets/Scripts/Server/WorldManager.cs

@@ -4,7 +4,6 @@ namespace ECSTest.Server
 {
     public struct WorldManager
     {
-        public EntityCollection<EntityType> entities;
-        public EntityDataBlockChain chain;
+        public EntityDatabase<EntityType, EntityDataBlockChain> bulletDatabase;
     }
 }