add riff homebrew tap

riff.rb

@@ -0,0 +1,27 @@
+require "FileUtils"
+
+class Riff < Formula
+  homepage "https://github.com/projectriff/riff"
+
+  v = "v0.1.0" # CI Managed
+  url "https://github.com/projectriff/riff/releases/download/#{v}/riff-darwin-amd64.tgz"
+  version v
+  sha256 "565b45b25650691cfd7219915b6e30ebe69c1b801b154d93c034e503857c0e45" # CI Managed
+
+  def gunzip(filename)
+    command = "gunzip --force #{filename}"
+    success = system(command)
+
+    success && $?.exitstatus == 0
+  end
+
+  def install
+    # FileUtils.mv("riff-darwin-amd64", "riff")
+    bin.install "riff"
+  end
+
+  test do
+    system "#{bin}/riff", "version"
+  end
+end
+