title: Rails 5 - Manually add attribute to parameters in controller when updating
body: <p>I am trying to manually add an additional attribute to parameters in the controller after completing a form.  The params seem to be wrapped in , which seems to be preventing me to from changing the params.</p>
  
  <p><strong>Controller:</strong></p>
  
  <pre><code>class ActualsController &lt; SignedInController
  ...
   def update
     respond_to do |format|
     facesheet = actual_params[:facesheet]
  
     #trying to manually add attribute
     actual_params.merge(:file_name =&gt; 'ted.png')
     new_params = actual_params.except(:facesheet)
  
        if @actual.update(new_params)
          format.html { redirect_to action: 'show', id:@actual.id, notice: 'Actual was successfully updated.' }
          format.json { render :show, status: :ok, location: @actual }
        else
          format.html { render :edit }
          format.json { render json: @actual.errors, status: :unprocessable_entity }
        end
  
     end
   end
  ...
  end
  </code></pre>
  
  <p><strong>"new_params" from console</strong></p>
  
  <pre><code>&lt;ActionController::Parameters {"encounter_type_id"=&gt;"1", "physician_id"=&gt;"669", "insurance_id"=&gt;"1182", "time_start"=&gt;"05:00", "time_end"=&gt;"07:00", "date_start"=&gt;"2017-08-02", "date_end"=&gt;"2017-08-02", "facility_id"=&gt;"1", "med_rec_num"=&gt;"1244", "patient_name_first"=&gt;"Bob", "patient_name_last"=&gt;"Smith", "patient_name_middle_initial"=&gt;"H", "patient_dob"=&gt;"2000-02-05", "note"=&gt;"", "is_complete"=&gt;"0", "procedure_ids"=&gt;["", "300"]} permitted: true&gt;  -Thanks for your help on this.
  </code></pre>
  
  <p><strong>"@actual" from console</strong></p>
  
  <pre><code>#&lt;Actual id: 18, encounter_id: 4, provider_id: 7, encounter_type_id: 1, physician_id: 669, facility_id: 1, insurance_id: 1182, group_id: nil, datetime_start_utc: "2017-08-02 10:00:00", datetime_end_utc: "2017-08-02 12:00:00", payer: nil, med_rec_num: "1244", patient_name_first: "Bob", patient_name_last: "Smith", patient_name_middle_initial: "H", patient_dob: "2000-02-05", finclass: nil, is_valid: nil, is_complete: false, image_location: nil, note: "", created_at: "2017-08-18 13:30:58", updated_at: "2017-08-18 16:01:28"&gt;
  </code></pre>