New formula: git-now

Closes Homebrew/homebrew#8169.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Formula/git-now.rb

@@ -0,0 +1,48 @@
+require 'formula'
+
+class GitNow < Formula
+  url 'https://github.com/iwata/git-now.git', :tag => 'v0.1.0.9'
+  version '0.1.0.9'
+  head 'https://github.com/iwata/git-now.git', :branch => 'develop'
+  homepage 'https://github.com/iwata/git-now'
+
+  depends_on 'gnu-getopt'
+
+  def options
+    [
+      ['--zsh-completion', "copy zsh completion function file to #{share}/zsh/functions"]
+    ]
+  end
+
+  def patches
+    DATA
+  end
+
+  def install
+    system "make", "prefix=#{prefix}", "install"
+    if ARGV.include? '--zsh-completion'
+      zsh_functions_d = share + 'zsh/functions'
+      zsh_functions_d.install "etc/_git-now"
+    end
+  end
+
+end
+
+# This patch makes sure GNUtools are used on OSX.
+# gnu-getopt is keg-only hence the backtick expansion.
+# These aliases only exist for the duration of git-now,
+# inside the git-now shells. Normal operation of bash is
+# unaffected - getopt will still find the version supplied
+# by OSX in other shells, for example.
+__END__
+--- a/git-now
++++ b/git-now
+@@ -1,5 +1,7 @@
+ #!/bin/sh
+
++alias getopt='`brew --prefix gnu-getopt`/bin/getopt'
++
+ # enable debug mode
+ if [ "$DEBUG" = "yes" ]; then
+   set -x
+