Added a rake task to install git hooks. Makes it easier to work with …

…plugins as submodules [ci skip]

lib/tasks/git.rake

@@ -0,0 +1,27 @@
+namespace :git do
+  desc "Install git submodule hooks and commands for easier development."
+  task :install_hooks do
+    postmerge_hook = ".git/hooks/post-merge"
+
+    File.delete postmerge_hook rescue true
+    File.open(postmerge_hook, 'w') do |f|
+      f.puts %Q{#!/bin/sh
+git submodule update}
+    end
+    File.chmod 0755, postmerge_hook
+    puts "=== Installed post-merge hook.\n    (Submodules will now be updated automatically.)"
+
+    submodules = File.open('.gitmodules', 'r').read.split("\n").map {|l|
+                     l[/submodule "(.*)"/, 1] }.compact
+
+    submodules.each do |submodule|
+      submodule_name = submodule.split("/").last
+      xpush_cmd = "!git push && cd ../../.. && git add #{submodule} && \
+git commit -m 'Updated #{submodule_name} submodule'"
+      system("cd #{submodule} && git config alias.xpush \"#{xpush_cmd}\"")
+    end
+
+    puts "=== Installed `git xpush` command on all submodules.\n    (Use it to push the submodule and commit the change to the superproject.)"
+  end
+end
+