Pass Contest Id into URL for search in Index - ruby-on-rails-3

Question

I have two models, contest and submission. submission belongs_to contest and contest has_many submissions.
In the index action for submissions I have a search:
def index
contest_id = params[:contest_id]
#contest = Contest.find(contest_id)
if params[:search].blank?
#submissions = Submission.paginate(:per_page => 10, :page => params[:page])
else
#submissions = Submission.search(params[:search]).paginate(:per_page => 10, :page => params[:page])
end
#search = params[:search]
end
I think the right way to pass it in is through the search form in the submissions>index view:
<div class ="span12 row">
<%= form_tag submissions_path, :method => 'get', :class => "form-search pull-right" do %>
<%= text_field_tag :search, params[:search], :class => 'input-xlarge', :placeholder => 'Search by member, title or description' %>
<%= submit_tag "Search", :title => nil, :class => 'btn btn-primary' %>
<% end %>
</div>
And I have been able to come close using this:
<%= hidden_field :contest_id, #contest.id %>
In the form, but it's returning this in the url:
http://localhost:3000/submissions?utf8=%E2%9C%93&search=test&contest_id%5B%5D=&commit=Search
And an error:
Couldn't find Contest with id=
I've also tried this:
<%= hidden_field(:contest_id, :value => #contest.id ) %>
But it's returning similar url and error.
Right now, I'm stuck. If you have any idea, please let me know.
[edit - added html]
Before search:
<div class ="span12 row">
<form accept-charset="UTF-8" action="/submissions" class="form-search pull-right" method="get"><div style="margin:0;padding:0;display:inline"><input name="utf8" type="hidden" value="✓" /></div>
<input class="input-xlarge" id="search" name="search" placeholder="Search by member, title or description" type="text" />
<input id="contest_id_5" name="contest_id[5]" type="hidden" />
<input class="btn btn-primary" name="commit" type="submit" value="Search" />
</form>
</div>
Here's what works from other links going to submissions:
From the submission show page:
<%= link_to 'Browse All Submissions', submissions_path(:contest_id => #contest.id), :class => 'btn btn-mini pull-right' %>`
and from the contest show page:
<%= link_to 'Browse All Submissions', submissions_path(:contest_id => #contest.id), :class => 'btn btn-mini pull-right' %>
Both of these pass the url "contest_id=5" which is what the controller needs to find a contest. The issue I'm having with search is finding the right syntax to get contest_id=5 to appear without the mumbo jumbo mucking it up.

Answer 1

This turned out to be an easy solution. Insert a hidden_field_tag in the search form:
<%= hidden_field_tag 'contest_id', #contest.id %>
This will pass the correct value into params:
http://localhost:3000/submissions?utf8=%E2%9C%93&search=new&contest_id=5&commit=Search