message: .gitignore: Remove *.bk
diff: # Generated by Cargo
  target/
  -# Generated by rustfmt
  -*.bk
  -
  # Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
  # More information here http://doc.crates.io/guide.html#cargotoml-vs-cargolock
  Cargo.lock
  