diff --git a/src/main/java/org/ntlab/tampoposerver/models/ChatRooms.java b/src/main/java/org/ntlab/tampoposerver/models/ChatRooms.java
index 542c07d..a5849b5 100644
--- a/src/main/java/org/ntlab/tampoposerver/models/ChatRooms.java
+++ b/src/main/java/org/ntlab/tampoposerver/models/ChatRooms.java
@@ -20,6 +20,9 @@
         this.chatRoomId = chatRoomId;
         this.user0Id = user0Id;
         this.user1Id = user1Id;
+
+        this.users.add(user0Id);
+        this.users.add(user1Id);
     }
 
     public String getUser0Id(){
@@ -81,4 +84,12 @@
         public String getSenderId() { return senderId;}
         public String getContent() { return content;}
     }
+
+    public boolean removeUser(String userId) {
+        return users.remove(userId);
+    }
+
+    public boolean isEmpty() {
+        return users.isEmpty();
+    }
 }