feat(navbar): add navbar with links to vuegg and gh-repo

Author: alxpez

_navbar.md

@@ -0,0 +1,4 @@
+<!-- _navbar.md -->
+
+* <a href="https://github.com/vuegg/vuegg" target="_blank" title="Vuegg on GH"><img width="30" src="/static/gh_logo.svg"></a>
+* <a href="https://vuegg.now.sh/" target="_blank" title="Go to Vuegg"><img width="30" src="/static/vuegg-plain.svg"></a>

index.html

@@ -27,10 +27,10 @@
     <script>
       window.$docsify = {
         name: 'vuegg',
-        repo: 'vuegg/vuegg',
         coverpage: true,
         auto2top: true,
         subMaxLevel: 2,
+        loadNavbar: true,
         loadSidebar: true,
         themeColor: '#ea493f'
       }