Channels: Include last message id on text channels.

API: Return members when fetching messages.
Misc: Remove defunct DISABLE_REGISTRATION variable.

src/routes/channels/message_query.rs

@@ -98,11 +98,20 @@ pub async fn req(user: User, target: Ref, options: Form<Options>) -> Result<Json
 
         ids.remove(&user.id);
         let user_ids = ids.into_iter().collect();
+        let users = user.fetch_multiple_users(user_ids).await?;
 
-        Ok(json!({
-            "messages": messages,
-            "users": user.fetch_multiple_users(user_ids).await?
-        }))
+        if let Channel::TextChannel { server, .. } = target {
+            Ok(json!({
+                "messages": messages,
+                "users": users,
+                "members": Server::fetch_members(&server).await?
+            }))
+        } else {
+            Ok(json!({
+                "messages": messages,
+                "users": users,
+            }))
+        }
     } else {
         Ok(json!(messages))
     }