add slack notification
add slack notification


Former-commit-id: 0a515f312a2fe4799ffe5bf53d232b4ecfb42769
alekseysidorov/exonum,exonum/exonum,alekseysidorov/exonum,alekseysidorov/exonum,alekseysidorov/exonum,exonum/exonum,exonum/exonum,exonum/exonum