Update Rakefile to manage pathogen-to-vundle upgrade

The Rakefile now detects if pathogen is installed and in that case
it performs the following operations:
1. Moves vim/bundle to vim/bundle.old
2. Removes all the submodules from git config and cache
3. Initializes and updates the new submodules (zsh and bundle)
4. Runs the vundle installer that takes care of the rest

Rakefile

@@ -1,4 +1,5 @@
 require 'rake'
+require 'fileutils'
 
 desc "Hook our dotfiles into system-standard positions."
 task :install => [:submodule_init, :submodules] do
@@ -18,7 +19,10 @@ task :install => [:submodule_init, :submodules] do
   file_operation(Dir.glob('ctags/*')) if want_to_install?('ctags config (better js/ruby support)')
   file_operation(Dir.glob('tmux/*')) if want_to_install?('tmux config')
   file_operation(Dir.glob('vimify/*')) if want_to_install?('vimification of command line tools')
-  file_operation(Dir.glob('{vim,vimrc}')) if want_to_install?('vim configuration (highly recommended)')
+  if want_to_install?('vim configuration (highly recommended)')
+    file_operation(Dir.glob('{vim,vimrc}')) 
+    Rake::Task["install_vundle"].execute
+  end
 
   Rake::Task["install_prezto"].execute
 
@@ -35,7 +39,9 @@ task :install_prezto do
   end
 end
 
-task :update => [:install] do
+task :update do
+  Rake::Task["vundle_migration"].execute if needs_migration_to_vundle?
+  Rake::Task["install"]
   #TODO: for now, we do the same as install. But it would be nice
   #not to clobber zsh files
 end
@@ -62,6 +68,49 @@ task :submodules do
   end
 end
 
+desc "Performs migration from pathogen to vundle"
+task :vundle_migration do
+  puts "======================================================"
+  puts "Migrating from pathogen to vundle vim plugin manager. "
+  puts "This will move the old .vim/bundle directory to" 
+  puts ".vim/bundle.old and replacing all your vim plugins with"
+  puts "the standard set of plugins. You will then be able to "
+  puts "manage your vim's plugin configuration by editing the "
+  puts "file .vim/vundles.vim"
+  puts "======================================================"
+
+  Dir.glob(File.join('vim', 'bundle','**')) do |sub_path|
+    run %{git config -f #{File.join('.git', 'config')} --remove-section submodule.#{sub_path}}
+    # `git rm --cached #{sub_path}`
+    FileUtils.rm_rf(File.join('.git', 'modules', sub_path))
+  end
+  FileUtils.mv(File.join('vim','bundle'), File.join('vim', 'bundle.old'))
+  run %{
+    cd $HOME/.yadr
+    git clone https://github.com/gmarik/vundle.git #{File.join('vim','bundle', 'vundle')}
+  }
+end
+
+desc "Runs Vundle installer in a clean vim environment"
+task :install_vundle do
+  puts "======================================================"
+  puts "Installing vundle."
+  puts "The installer will now proceed to run BundleInstall."
+  puts "Due to a bug, the installer may report some errors"
+  puts "when installing the plugin 'syntastic'. Fortunately"
+  puts "Syntastic will install and work properly despite the"
+  puts "errors so please just ignore them and let's hope for"
+  puts "an update that fixex the problem!"
+  puts "======================================================"
+
+  puts ""
+  puts "Press a key to continue"
+  STDIN.getc
+  
+  system "vim --noplugin -u vim/vundles.vim -N \"+set hidden\" \"+syntax on\" +BundleClean +BundleInstall +qall"
+  
+end
+
 task :default => 'install'
 
 
@@ -194,6 +243,17 @@ def file_operation(files, method = :symlink)
   end
 end
 
+def needs_migration_to_vundle?
+  File.exists? File.join('vim', 'bundle', 'tpope-vim-pathogen')
+end
+
+
+def list_vim_submodules
+  result=`git submodule -q foreach 'echo $name"||"\`git remote -v | awk "END{print \\\\\$2}"\`'`.select{ |line| line =~ /^vim.bundle/ }.map{ |line| line.split('||') }
+  Hash[*result.flatten]
+end
+
+
 def success_msg(action)
   puts ""
   puts "   _     _           _         "