feat($core): config pattern of resolved files

packages/@vuepress/core/lib/node/App.js

@@ -316,7 +316,9 @@ module.exports = class App {
 
   async resolvePages () {
     // resolve pageFiles
-    const patterns = ['**/*.md', '**/*.vue', '!.vuepress', '!node_modules']
+    const patterns = this.siteConfig.patterns ? this.siteConfig.patterns : ['**/*.md', '**/*.vue']
+    patterns.push('!.vuepress', '!node_modules')
+
     if (this.siteConfig.dest) {
       // #654 exclude dest folder when dest dir was set in
       // sourceDir but not in '.vuepress'

packages/@vuepress/core/lib/node/__tests__/prepare/fixtures/docs-patterns/.vuepress/config.js

@@ -0,0 +1,10 @@
+module.exports = {
+  title: 'Hello VuePress',
+  description: '# Hello, VuePress!',
+  dest: 'vuepress',
+  base: 'vuepress',
+  patterns: ['**/*.md', '**/*.vue', '!**/deploy.*'],
+  head: [
+    ['link', { rel: 'icon', href: '/logo.png' }]
+  ]
+}

packages/@vuepress/core/lib/node/__tests__/prepare/fixtures/docs-patterns/README.md

@@ -0,0 +1 @@
+# Hello, VuePress!

packages/docs/docs/config/README.md

@@ -131,6 +131,13 @@ module.exports = {
 }
 ```
 
+### patterns
+
+- Type: `Array`
+- Default: `['**/*.md', '**/*.vue']`
+
+Specify which pattern of files you want to be resolved.
+
 ## Styling
 
 ### palette.styl

packages/docs/docs/zh/config/README.md

@@ -127,6 +127,13 @@ module.exports = {
 }
 ```
 
+### patterns
+
+- Type: `Array`
+- Default: `['**/*.md', '**/*.vue']`
+
+Specify which pattern of files you want to be resolved.
+
 ## Styling
 
 ### palette.styl