after bitly repo was frozen, pusher is now the official hard fork https://github.com/bitly/oauth2_proxy/issues/628
https://github.com/NixOS/nixpkgs/pull/17254#issuecomment-245295541 * update docs to describe `deps.nix` * include goDeps in nix-shell GOPATH * NixOS 16.09 rel notes about replacing goPackages