Rebuild docsify and delete docs caching code

docs/lib/plugins/ga.js

@@ -0,0 +1,43 @@
+(function () {
+  /* eslint-disable no-console */
+  // From https://github.com/egoist/vue-ga/blob/master/src/index.js
+  function appendScript() {
+    var script = document.createElement('script');
+    script.async = true;
+    script.src = 'https://www.google-analytics.com/analytics.js';
+    document.body.appendChild(script);
+  }
+
+  function init(id) {
+    appendScript();
+    window.ga =
+      window.ga ||
+      function () {
+        (window.ga.q = window.ga.q || []).push(arguments);
+      };
+
+    window.ga.l = Number(new Date());
+    window.ga('create', id, 'auto');
+  }
+
+  function collect() {
+    if (!window.ga) {
+      init($docsify.ga);
+    }
+
+    window.ga('set', 'page', location.hash);
+    window.ga('send', 'pageview');
+  }
+
+  var install = function (hook) {
+    if (!$docsify.ga) {
+      console.error('[Docsify] ga is required.');
+      return;
+    }
+
+    hook.beforeEach(collect);
+  };
+
+  $docsify.plugins = [].concat(install, $docsify.plugins);
+
+}());