feat: publicize doc implemetation

one/docs/demo/checkbox-group/default.vue

@@ -0,0 +1,65 @@
+<template>
+<article>
+  <section>
+    <h4>Normal size</h4>
+    <veui-checkbox-group
+      v-model="selected"
+      :items="licenses"
+    />
+    <p>Checked: {{ readable }}</p>
+  </section>
+  <section>
+    <h4>Small size</h4>
+    <veui-checkbox-group
+      v-model="selected"
+      ui="s"
+      :items="licenses"
+    />
+    <p>Checked: {{ readable }}</p>
+  </section>
+</article>
+</template>
+
+<script>
+import { CheckboxGroup } from 'veui'
+
+export default {
+  components: {
+    'veui-checkbox-group': CheckboxGroup
+  },
+  data () {
+    return {
+      selected: null,
+      licenses: [
+        {
+          label: 'MIT License',
+          value: 'mit'
+        },
+        {
+          label: 'BSD License',
+          value: 'bsd'
+        },
+        {
+          label: 'Apache License 2.0',
+          value: 'apache2'
+        }
+      ]
+    }
+  },
+  computed: {
+    readable () {
+      return (this.selected || []).join(', ') || '-'
+    }
+  }
+}
+</script>
+
+<style lang="less" scoped docs>
+section {
+  margin-bottom: 20px;
+}
+
+h4 {
+  margin-top: 0;
+}
+</style>