Add derivation for phlay

phlay-overlay.nix

@@ -0,0 +1,5 @@
+self: super:
+
+{
+  phlay = super.callPackage ./pkgs/phlay {};
+}

pkgs/phlay/default.nix

@@ -0,0 +1,26 @@
+{ fetchFromGitHub
+, python36Packages
+}:
+python36Packages.buildPythonApplication {
+  name = "phlay";
+  version = "0.1.2";
+  src = fetchFromGitHub {
+    owner = "mystor";
+    repo = "phlay";
+    rev = "0deedf7397e2133bf270c41136c7650433610d4e";
+    sha256 = "1jdxk0a551zcfq6j8cp6ajm4dvsp7c0rqbdkk7h3lpdvws24z0n6";
+  };
+  meta = {
+    description = "A command-line interface for Phabricator";
+    longDescription = ''
+      Phlay is an alternative to Arcanist for submitting changes to Phabricator.
+
+      You might like Phlay if you do Mozilla development using git and
+      a "commit series" workflow.
+    '';
+  };
+  # phlay is designed as a single-file Python script with no
+  # dependencies outside the stdlib.
+  format = "other";
+  installPhase = "mkdir -p $out/bin; cp phlay $out/bin";
+}