Rails - Dynamic form with radio buttons - ruby-on-rails

Question

Basically I'm trying to list all events from my database on a website using this code:
<table class="table">
<thead>
<tr>
<th>Event</th>
<th>Join Event?</th>
</tr>
</thead>
<tbody>
<% #events.each do |e| %>
<p>
<tr>
<td>
<div>
<%= e.name %>
</div>
</td>
<td>
<div class="btn-group" data-toggle="buttons-radio">
<button class="btn" class-toggle="btn-success"><i class="icon-ok"></i></button>
<button class="btn btn-danger active" class-toggle="btn-danger"><i class="icon-remove"></i></button>
</div>
</td>
</tr>
</tbody>
<% end %>
</table>
You can easily join an event by clicking on a radio button. Now my problem is how can I save this form in Rails? In this example I have joined(=clicked) Event 2. What is the best way to save this form back into the database. Ideally I have a "Update" or "Save" button at the end of the website, which does that for me.
But when I add a simple submit button like this to the my form
...same code as above
</td>
</tr>
</tbody>
<%= f.submit 'Save form' %>
<% end %>
</table>
then my submit button will be triggered everytime I click on one of my radio buttons. Does anyone know a fix to this problem?

Answer 1

well, it is fairly simple to do a event[] radio button that when submitted will submit an array of the selected options.
The button tags would look like this, adjusting for your classes etc.
<%= radio_button_tag event[], e.id %>
then the controller would look like
def create
...
user.events = params[:event] unless params[:event].empty?
user.save
...
end
This ofcoarse assumes that you have a column in your user model to store events they are going to. A more flexible model would be to have user :has_many events :through => user_events. The same controller logic would apply, except it would look like
def create
...
if params[:event]
params[:event].each do |e|
user.user_event.new(:event_id => e)
end
end
....
end
Resources:
Form tag helpers: here
Using :has_many :through associations : here (section 2.4)