travis: simplify

pkgs/development/tools/misc/travis/default.nix

···
-{ stdenv, lib, bundlerEnv, ruby }:
+{ lib, bundlerEnv, ruby }:
 
-stdenv.mkDerivation rec {
-  name = "travis-${version}";
-  version = env.gems.travis.version;
-
-  env = bundlerEnv {
-    inherit ruby;
-    name = "${name}-gems";
-    gemset = ./gemset.nix;
-    gemfile = ./Gemfile;
-    lockfile = ./Gemfile.lock;
-  };
-
-  phases = ["installPhase"];
-
-  installPhase = ''
-    mkdir -p $out/bin
-    ln -s ${env}/bin/travis $out/bin/travis
-  '';
+bundlerEnv {
+  inherit ruby;
+  pName = "travis";
+  gemdir = ./.;
 
   meta = with lib; {
     description = "CLI and Ruby client library for Travis CI";
     homepage    = https://github.com/travis-ci/travis.rb;
     license     = licenses.mit;
     maintainers = with maintainers; [ zimbatm ];
-    platforms   = ruby.meta.platforms;
   };
 }