docs: documentation theme logo (#1150)

Author: matthieumota

docs/.vuepress/config.js

@@ -29,6 +29,7 @@ module.exports = {
     repo: 'vuejs/vuepress',
     editLinks: true,
     docsDir: 'docs',
+    docsBranch: '0.x',
     // #697 Provided by the official algolia team.
     // algolia: {
     //   apiKey: '3a539aab83105f01761a137c61004d85',

docs/default-theme-config/README.md

@@ -39,6 +39,19 @@ If you want to use a completely custom homepage layout, you can also use a [Cust
 
 The Navbar may contain your page title, [Search Box](#search-box), [Navbar Links](#navbar-links), [Languages](../guide/i18n.md) and [Repository Link](#git-repo-and-edit-links), all of them depends on your configuration.
 
+### Navbar Logo
+
+You can add a logo to the navbar via `themeConfig.logo`. Logo can be placed in [public folder](../guide/assets.md#public-files).
+
+``` js
+// .vuepress/config.js
+module.exports = {
+  themeConfig: {
+    logo: '/assets/img/logo.png',
+  }
+}
+```
+
 ### Navbar Links
 
 You can add links to the navbar via `themeConfig.nav`: