You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: firefox.rb
    path of file: ./repos/vernier/lib/vernier/output
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

require "json"
require "rbconfig"

module Vernier
  module Output
    # https://profiler.firefox.com/
    # https://github.com/firefox-devtools/profiler/blob/main/src/types/profile.js
    class Firefox
      class Categorizer
        attr_reader :categories
        def initialize
          @categ
    
        def initialize
          @categories = []
          @categories_by_name = {}

          add_category(name: "Default", color: "grey")
          add_category(name: "Idle", color: "transparent")

          add_category(name: "GC", color: "red")
          add_category(
            name: "stdlib",
            color: "red",
            matcher: starts_with(RbConfig::CONFIG["rubylibdir"])
          )
          add_category(name: "cfunc", color: "yellow", matcher: "<cfunc>")

          rails_components = %w[ activesupport activemodel activerecord
          actionview actionpack activejob actionmailer actioncable
          activestorage actionmailbox actiontext railties ]
          add_category(
            name: "Rails",
            color: "green",
            matcher: gem_path(*rails_components)
          )
          add_category(
            name: "gem",
            color: "red",
            matcher: starts_with(*Gem.path)
          )
          add_category(
            name: "Application",
            color: "purple"
          )

          add_category(name: "Thread", color: "grey")
        end