chore: add docs site

package.json

@@ -39,6 +39,8 @@
     "build:es": "rimraf es && babel src --env-name es --out-dir es --ignore 'src/browser.js'",
     "build:other": "rimraf lib && rollup -c scripts/rollup.config.js",
     "codecov": "codecov",
+    "docs": "vuepress dev --host 0.0.0.0 --port 3000 docs",
+    "docs:build": "vuepress build docs",
     "predeploy": "git checkout master && git pull -r",
     "deploy": "npm version",
     "postdeploy": "git push origin master --follow-tags && npm run release",
@@ -57,6 +59,9 @@
     "lodash.isplainobject": "^4.0.6",
     "lodash.uniqueid": "^4.0.1"
   },
+  "resolutions": {
+    "webpack-dev-middleware": "3.6.0"
+  },
   "devDependencies": {
     "@babel/cli": "^7.2.3",
     "@babel/core": "^7.3.3",
@@ -91,9 +96,14 @@
     "rollup-plugin-node-resolve": "^4.0.0",
     "rollup-plugin-terser": "^4.0.4",
     "update-section": "^0.3.3",
-    "vue": "^2.6.6",
-    "vue-jest": "^3.0.3",
-    "vue-server-renderer": "^2.6.6",
-    "vue-template-compiler": "^2.6.6"
+    "vue": "^2.6.8",
+    "vue-jest": "^3.0.4",
+    "vue-loader": "^15.7.0",
+    "vue-router": "^3.0.2",
+    "vue-server-renderer": "^2.6.8",
+    "vue-template-compiler": "^2.6.8",
+    "vuepress": "^0.14.10",
+    "vuepress-theme-vue": "^1.1.0",
+    "webpack": "^4.29.6"
   }
 }