这很难回答，因为您遇到的问题是要求我们决定您的应用程序将如何工作。您必须自己做，并进行适当的设计和维护。

It's difficult to answer because the sort of questions you're asking require us to decide how your application will work. You have to do that yourself and make appropriate design & programming based on your decision.

对于HABTM记录的显示，我通常使用复选框或某些图形只读形式。

As for display of HABTM records, I usually use checkboxes or some graphical readonly equivalent.

我的建议是您环顾网络，看看它如何在其他网站上工作-Flickr和Facebook等社交网站是一个不错的狩猎场，因为它们有很多的组，类别等。

My suggestion is that you look around the web to see how it works on other sites - social sites like Flickr and Facebook are a good hunting ground as they have lots of groups, categories etc.