implement admin command to force join list of local users

Signed-off-by: strawberry <strawberry@puppygock.gay>

src/admin/user/mod.rs

@@ -124,4 +124,19 @@ pub(super) enum UserCommand {
 	RedactEvent {
 		event_id: Box<EventId>,
 	},
+
+	/// - Force joins a specified list of local users to join the specified
+	///   room.
+	///
+	/// Specify a codeblock of usernames.
+	///
+	/// At least 1 server admin must be in the room to prevent abuse.
+	///
+	/// Requires the `--yes-i-want-to-do-this` flag.
+	ForceJoinListOfLocalUsers {
+		room_id: OwnedRoomOrAliasId,
+
+		#[arg(long)]
+		yes_i_want_to_do_this: bool,
+	},
 }