def env(prefix='GH_')
      @envs ||= begin
        envs = ENV.select { |env| env.start_with? prefix }
                  .map { |k, v| [k.sub(/^#{prefix}/, ''), v] }
        down_symbolize_key(envs)
      end
      @envs.merge(dotenv)
    end
def env(prefix='GH_')
      @envs ||= begin
        envs = ENV.select { |env| env.start_with? prefix }
                  .map { |k, v| [k.sub(/^#{prefix}/, ''), v] }
        down_symbolize_key(envs)
      end
      @envs.merge(dotenv)
    end
returns: ENV variables prefixed with 'GH_'(default)
          and variables defined in dotenv file.