2.1.0

• Drop support to Rails 3 applications.
• Respect Rails.public_path when computing the path to the manifest file.
• Restore config.assets.manifest option, which was removed in Rails 4.0.0.
  This change does not affect existing behavior if the option is not set.
• Respect asset_host and relative_url_root to invalidate cache.
• Assets not in the precompile list can be checked for errors by setting
  config.assets.raise_runtime_errors = true in any environment

2.0.1

• Allow keep value to be specified for assets:clean run with args
  for example assets:clean[0] will keep no old asset copies
• Fix javascript_include_tag/stylesheet_include_tag helpers when debug: => false is used.
• Fix issue when precompiling html.erb files. Fixes #45.