Script Ruby filter plugin for Embulk

TODO: Write short description here and embulk-filter-script_ruby.gemspec file.

• Plugin type: filter

• script: script file (string, required)
• class: class name (string, required)
• columns: output columns (array, default: null)

filters:
  - type: script_ruby
    script: filter_hoge
    class: FilterHoge
    columns:
      - {name: id, type: string}
      ...

filter_hoge.rb

class FilterHoge
  def initialize()
    ...
  end
  
  def filter(record)
    ...
    record
  end
end

$ embulk run -I lib config.yml

$ rake