add post and fix bugs, also use external

src/layouts/Sidebar.vue

@@ -6,7 +6,7 @@ div
 
       Highlight text and press "s" to speak.
     a.twitter-timeline(href="https://twitter.com/ChinesePol" data-height="600") Tweets by ChinesePol
-  b-card
+  b-card.mb-3
     h3 Tag cloud
     span.mr-3(v-for="t in tags" :key="t.name" :class="t.class")
       b-link(:to="'/tag/' + t.name") {{t.name}}