Pål Bergström wrote:
<label for="group_user.company">Organisation</label> <%= text_field "group", "user.company" %><br/>
No, you can't do this. Instead, set @user = @group.user in your controller, code the field as
<%= text_field :user, :company %>
and deal with both params[:user] and params[:group] in your controller. Exactly what you do depends on the new/existing status of both the group and user records.