hexo-theme-amane/layout/plugin/google-analytics.ejs

<script type="text/javascript">
(function(i,s,o,g,r,a,m) {i['GoogleAnalyticsObject']=r;i[r]=i[r]||function() {
(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
})(window,document,'script','//www.google-analytics.com/analytics.js','ga');

ga('create', '<%= theme.plugins.google_analytics %>', 'auto');
ga('send', 'pageview');

</script>