message: Switch off nightly in CI
diff: @@ -22,7 +22,7 @@ version: 2
  jobs:
  build:
  docker:
  - - image: rustlang/rust:nightly
  + - image: rust:1.39.0
  environment:
  RUSTFLAGS: -D warnings
  - image: sfackler/rust-postgres-test:5
  