title: .build method doesn't want to do both _id's when object has two :belongs_to...?
body: <p>I have an object called Review which :belongs_to two objects: Users and Vendors.  In other words, there is always a vendor writing a review for a specific vendor.</p>
  
  <p>When I create a review, I tried to use the .build method to presumably add the foreign_key at the time the new record is created for review.vendor_id and review.user_id.</p>
  
  <p>When I put into the controller for review the build statement for user id without one for capturing the vendor id, it works like a charm.  When I add the vendor_id the user_id stays 'nil'.</p>
  
  <p>Help?  Reviews is a nested resource:  vendors/3/reviews/new</p>
  
  <p>Forms for review/new:</p>
  
  <pre><code>&lt;% form_for [@vendor, @review] do |f| %&gt;
  </code></pre>
  
  <p>In the review controller:</p>
  
  <pre><code>    def new
        @vendor = Vendor.find(params[:vendor_id])
        @review = @vendor.reviews.build
        #@review = Review.new
      end
  
  
  
  def create
      @vendor = Vendor.find(params[:vendor_id])
      @review = @current_analyst.reviews.build params[:review]
  
      if @review.save
        flash[:notice] = "Successfully created review."
        redirect_to review_path(@review)
      else
    render :action =&gt; 'new'
  end
  </code></pre>
  
  <p>end</p>