grails-ui datatable in-line cell editing and dropdowns

Another post about almost the same topic. How to feed the dropdown options for the in-line editing with values from the database. It is quite simple, although I was running in the wrong direction for some time and I was not the first one with this problem.

The simple answer is: you have to add a groovy collection to your model like this (I wanted to be able to choose a user, so I collected user names from the spring security core user class)

def userNames = User.list().collect{it.username}
render(template: '/layouts/template', model: [userNames: userNames])

Now you can do it like this:

..., config:[dropdownOptions: userNames, disableBtns:true]],...