gistfile1.rb

  def show
    @company = Company.find(params[:id], :include => :company_location)
 
    respond_to do |format|
      format.html # show.html.erb
      format.json { render json: @company }
    end
  end
 
 
<%= @company.company_name %> @ <%= @company.company_location %>

Output:
ChocoLát Beauty @ [#<CompanyLocation deal_id: 0, company_id: 1, lng: "34434", lat: "3434", address: "fdfsfd">]

<%= @company.company_name %> @ <%= @company.company_location.address %>

Output (error):
undefined method `address' for #<ActiveRecord::Relation:0x007fc55b6793c8>