feat(chat): add placeholder modal for new room

lib/slax_web/live/chat_room_live.ex

@@ -46,6 +46,12 @@ defmodule SlaxWeb.ChatRoomLive do
                 >
                   Browse rooms
                 </.link>
+                <.link
+                  class="block select-none cursor-pointer whitespace-nowrap text-gray-800 hover:text-white px-6 py-1 hover:bg-sky-600"
+                  phx-click={show_modal("new-room-modal")}
+                >
+                  Create a new room
+                </.link>
               </div>
             </div>
           </div>
@@ -203,6 +209,10 @@ defmodule SlaxWeb.ChatRoomLive do
         </div>
       </div>
     </div>
+    <.modal id="new-room-modal">
+      <.header>New chat room</.header>
+      (Form goes here)
+    </.modal>
     """
   end