bundle-update-lockfile.rb

#!/usr/bin/env ruby

require 'bundler'

gems = ARGV

if gems.empty?
  puts "Updating all gems"

  Bundler.definition(true)
else
  puts "Updating gems: #{gems.join(', ')}"

  lock = Bundler.read_file(Bundler.default_lockfile)
  names = Bundler::LockfileParser.new(lock).specs.map{ |s| s.name }

  gems.each do |g|
    next if names.include?(g)
    puts "Unable to find '#{g}'"
  end

  Bundler.definition(:gems => gems, :sources => [])
end

d = Bundler.definition

puts "Resolving remotely..."

d.resolve_remotely!
d.lock(Bundler.default_lockfile)

puts "Updated lockfile! Enjoy!"