def show
      group = Group.find_by(id: params[:id])
      membership = Membership.find_by(group_id: group.id)

      respond_to do |format|
        format.html do
          render :show, locals: { group: group, membership: membership }
        end
      end
    end
def show
      group = Group.find_by(id: params[:id])
      membership = Membership.find_by(group_id: group.id)

      respond_to do |format|
        format.html do
          render :show, locals: { group: group, membership: membership }
        end
      end
    end
GET /groups/1