helm (kubernetes): init at v2.0.2

Added a nix expression to download and install helm; added it to top
level packages as kubernetes_helm.

pkgs/applications/networking/cluster/helm/default.nix

@@ -0,0 +1,42 @@
+{ stdenv, fetchurl, kubernetes }:
+let
+  arch = if stdenv.isLinux
+         then "linux-amd64"
+         else "darwin-amd64";
+  checksum = if stdenv.isLinux
+             then "dad3791fb07e6cf34f4cf611728cb8ae109a75234498a888529a68ac6923f200"
+             else "d27bd7e40e12c0a5f08782a8a883166008565b28e0b82126d2089300ff3f8465";
+in
+stdenv.mkDerivation rec {
+  pname = "helm";
+  version = "2.0.2";
+  name = "${pname}-${version}";
+
+  src = fetchurl {
+    url = "https://kubernetes-helm.storage.googleapis.com/helm-v${version}-${arch}.tar.gz";
+    sha256 = "${checksum}";
+  };
+
+  buildInputs = [ ];
+
+  propagatedBuildInputs = [ kubernetes ];
+
+  phases = [ "buildPhase" "installPhase" ];
+
+  buildPhase = ''
+    mkdir -p $out/bin
+  '';
+
+  installPhase = ''
+    tar -xvzf $src
+    cp ${arch}/helm $out/bin/${pname}
+    chmod +x $out/bin/${pname}
+  '';
+
+  meta = with stdenv.lib; {
+    homepage = https://github.com/kubernetes/helm;
+    description = "A package manager for kubernetes";
+    license = licenses.asl20;
+    platforms = platforms.linux ++ platforms.darwin;
+  };
+}

pkgs/top-level/all-packages.nix

@@ -13341,6 +13341,8 @@ in
 
   hello = callPackage ../applications/misc/hello { };
 
+  kubernetes_helm = callPackage ../applications/networking/cluster/helm { };
+
   helmholtz = callPackage ../applications/audio/pd-plugins/helmholtz { };
 
   heme = callPackage ../applications/editors/heme { };