Send description and tag_list during registration

If specified RUNNER_DESCRIPTION or RUNNER_TAG_LIST can be send during registration. By default hostname is used for description.

lib/config.rb

@@ -17,12 +17,6 @@ module GitlabCi
end
end
-    def hostname
-      @config.fetch('hostname') do
-        Socket.gethostname
-      end
-    end
-
def token
@config['token']
end