I'm making a chat room now. On the screen to create a room, select the user to enter the room, but currently only current_user and another user can enter the room. Using check_box etc.
What if I want to have more than one user in my room?

Reference (chat room creation screen)
Link content

[View file of room creation page]

   New chat room 
<% = form_with model: @room, local: true do | f |%>
    
      
      <% = f.label: Chat room name, class:'chat-room-form__label'%>
      
      
      <% = f.text_field: name, class:'chat__room_name chat-room-form__input', placeholder:'Please enter the chat room name'%>
      
    
    
    
    
      
      <label class ='chat-room-form__label' for ='chat_room_ chat member'>chat member</label>
      
      
      <select name = "room [user_ids] []">
        <option value = "">Please select the user to chat with</option>
        <% User.where.not (id: current_user.id) .each do | user |%>
         <option value =<% = user.id% >><% = user.name%></option>
      <% end%>
      </select>
      <input name = "room [user_ids] []" type = "hidden" value =<% = current_user.id% >>
      
    
    
       
      
      <% = f.submit class:'chat-room-form__action-btn'%>
      
    
<% end%>

[Rooms.controller.rb]
class RoomsController

[Users.controller.rb]
class UsersController