New formula for git-imerge

git-imerge performs a merge between two branches incrementally. If
conflicts are encountered, figure out exactly which pairs of commits
conflict, and present the user with one pairwise conflict at a time for
resolution.

Closes Homebrew/homebrew#27042.

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

Formula/git-imerge.rb

@@ -0,0 +1,15 @@
+require "formula"
+
+class GitImerge < Formula
+  homepage "https://github.com/mhagger/git-imerge"
+  url "https://github.com/mhagger/git-imerge/archive/0.7.0.tar.gz"
+  sha1 "b3bab94743a79426ea79c1b5e503020ef7fbf2ec"
+
+  def install
+    bin.install "git-imerge"
+  end
+
+  test do
+    system "#{bin}/git-imerge", "-h"
+  end
+end