add submitters template_id filter

app/controllers/api/submitters_controller.rb

@@ -10,6 +10,11 @@ module Api
       submitters = submitters.where(external_id: params[:application_key]) if params[:application_key].present?
       submitters = submitters.where(external_id: params[:external_id]) if params[:external_id].present?
       submitters = submitters.where(submission_id: params[:submission_id]) if params[:submission_id].present?
+
+      if params[:template_id].present?
+        submitters = submitters.joins(:submission).where(submission: { template_id: params[:template_id] })
+      end
+
       submitters = maybe_filder_by_completed_at(submitters, params)
 
       submitters = paginate(