class TopicsCell < Cell::Rails
  def hot_sections
    @sections= Section.all.includes(:nodes)
    render
  end
end

The operation: #<Moped::Protocol::Query
  @length=80
  @request_id=129
  @response_to=0
  @op_code=2004
  @flags=[:slave_ok]
  @full_collection_name="ruby_china_dev.nodes"
  @skip=0
  @limit=0
  @selector={"section_id"=>{"$in"=>0}}
  @fields=nil>
failed with error 12580: "invalid query"

See https://github.com/mongodb/mongo/blob/master/docs/errors.md
for details about this error.


1: <div id="sections" class="box">
2:     <h2><%= t("common.index_node_navigation")%></h2>
3:     <ul>
4:         <% @sections.each do |section| %>
5:         <li>
6:             <label><%= section.name %></label>
7:             <span class="nodes">