def update
      authorize! :update, @membership
      if @membership.update(membership_params)
        redirect_to participant_path(@participant),
                    notice: "Group assignment was successfully updated."
      else
        flash[:alert] = @membership.errors.full_messages.join(", ")
        flash[:alert] += "End date cannot be set prior to tomorrow's date. " \
                           "Please use [Discontinue] or [Terminate Access] " \
                           "from the patient dashboard."
        render :edit
      end
    end
def update
      authorize! :update, @membership
      if @membership.update(membership_params)
        redirect_to participant_path(@participant),
                    notice: "Group assignment was successfully updated."
      else
        flash[:alert] = @membership.errors.full_messages.join(", ")
        flash[:alert] += "End date cannot be set prior to tomorrow's date. " \
                           "Please use [Discontinue] or [Terminate Access] " \
                           "from the patient dashboard."
        render :edit
      end
    end
PATCH/PUT /think_feel_do_dashboard/participants/1/groups/1