Use Node 8.x for now for Docker
Use Node 8.x for now for Docker

sqlite3 doesn't have binaries for latest Node 9.x versions.
Fixes: #503

sysgears/apollo-universal-starter-kit,sysgears/apollo-universal-starter-kit,sysgears/apollo-fullstack-starter-kit,sysgears/apollo-universal-starter-kit,sysgears/apollo-universal-starter-kit