Question

I’m working on the view for editing a project, which contain of a form with all the project fields, and for the members of a project I render out checkboxes.

When the form is submitted and the controller takes over I remove the array of members from the param so I can update the project correctly. However, what I wonder is what code I should use to update the table projects_users with the members (now in the array @members)?

edit project view:

<%= form_for @project do |f| %>
    ...
        the rest of the form
    ...
    <div class="checkbox">
        <% @members.each do |user| %>
            <%= check_box_tag "project[members][]", user.id, '1', :id => "user_#{user.id}" %> 
            <%= label_tag "user_#{user.id}", user.first_name + ' ' + user.last_name, :class => "checkbox" %>
        <% end %>
    </div>
    ...
        the rest of the form
    ...
<% end %>

projects controller:

...
def update
  @project = Project.find(params[:id])
  @members = params[:project].delete(:members)

  if @project.update_attributes(params[:project])

    ... code for updating projects_users? ...

    redirect_to users_projects_path
    flash.now[:success] = 'Projektet redigerades.' # Not quite right!
  else
    render :action => "edit"
  end
end
...

the table projects_users:

t.integer "project_id"
t.integer "user_id"

Answer 1

Use the user_ids attribute of Project to update its users:

# In the view:
<%= check_box_tag "project[user_ids][]", user.id, '1', :id => "user_#{user.id}" %> 


# In the controller:
@project = Project.find(params[:id])

#@members = params[:project].delete(:members)
# you don't need this line since :
# params[:project][:members] became params[:project][:user_ids]

if @project.update_attributes(params[:project])
  #...