Add script to migrate object dbs
user
```ruby
#!/usr/bin/env ruby
# Migrates .yardocs to --single-db
$:.unshift(File.dirname(__FILE__) + '/../')
$:.unshift(File.dirname(__FILE__) + '/../lib')
$:.unshift(File.expand_path(File.dirname(__FILE__) + '/../yard/lib'))

require 'yard'
require 'init'

include YARD

[File.join(REPOS_PATH, '*', '*', '*'), File.join(REMOTE_GEMS_PATH, '*', '*', '*')].each do |dir|
  Dir[dir].each do |d| 
    puts ">> Migrating .yardoc to single db for #{d}"
    Dir.chdir(d)
    Registry.load!
    Registry.save
    `touch .yardoc/complete`
  end
end
```
assistant