database relations grouping items

Hi I'm creating an online tool allowing users to add items of clothing to their account. I want to allow users to group these items but am unsure when it comes to the database relationships.

Items are added by users;

Multiple items should then be able to be grouped together;

A single item should be able to be in more than one group.

Before the grouping feature I had one table for users and one table for items, linked via a primary/foreign key. Then to get items from a specific user I simply joined the two tables and selected entries by user_id.

I'm unsure how I should go about implementing the groups feature

Should I have a table for groups and how should they relate ?

I'm really new to database relations but if I have a table ca开发者_StackOverflow社区lled groups, how can it have an array of items as an entry? or how can an item have an array of groups that it belongs to ?

any help would be brilliant

Tables

USER
-----
userID (pk)  


GROUP
------
groupID  (pk)  
userID   (fk)



GROUP_ITEMS
---------
groupID (pk)  
itemID  (pk)  


ITEM
----
ItemID (pk)  

Be aware the "GROUP" will most likely be a reserved/keyword so you may want to rename it.