diff --git a/src/domain/chat_room.rs b/src/domain/chat_room.rs
index e76dc84..46c0f52 100644
--- a/src/domain/chat_room.rs
+++ b/src/domain/chat_room.rs
@@ -12,3 +12,9 @@ pub struct ChatRoom {
     #[serde(rename = "lastUpdated")]
     pub last_updated: DateTime<Utc>,
 }
+
+impl ChatRoom {
+    pub fn new(title: String, owner_id: u32) -> Self {
+        Self { id: 0, title, owner_id, time_created: Utc::now(), last_updated: Utc::now() }
+    }
+}
\ No newline at end of file
diff --git a/src/domain/chat_user.rs b/src/domain/chat_user.rs
new file mode 100644
index 0000000..3e9e6ec
--- /dev/null
+++ b/src/domain/chat_user.rs
@@ -0,0 +1,9 @@
+use serde::{Deserialize, Serialize};
+use chrono::{DateTime, Utc};
+
+#[derive(Debug, Serialize, Deserialize, Clone, PartialEq, Eq, PartialOrd, Ord, Default)]
+pub struct ChatUser {
+    pub chat_room_id: u32,
+    pub user_id: u32,
+    pub time_joined: DateTime<Utc>,
+}
\ No newline at end of file
diff --git a/src/domain/mod.rs b/src/domain/mod.rs
index fd060f5..effbc4f 100644
--- a/src/domain/mod.rs
+++ b/src/domain/mod.rs
@@ -1,3 +1,4 @@
 pub mod chat_message;
 pub mod chat_message_update;
-pub mod chat_room;
\ No newline at end of file
+pub mod chat_room;
+pub mod chat_user;
\ No newline at end of file
diff --git a/src/lib.rs b/src/lib.rs
index ae4439e..39113e4 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1 +1,2 @@
-pub mod domain;
\ No newline at end of file
+pub mod domain;
+pub mod dto;
\ No newline at end of file