feat(user): user text

src/view/users-add.vue

@@ -14,7 +14,7 @@
       <el-input v-model="data.nickName" style="width: 300px" :maxlength="500" placeholder="请输入" />
     </el-form-item>
     <el-form-item label="账号" prop="userName" required>
-      <el-input v-model="data.userName" style="width: 300px" :maxlength="500" placeholder="请输入字母或数字组合" />
+      <el-input v-model="data.userName" style="width: 300px" :maxlength="500" placeholder="请输入16位内字母或数字组合" />
     </el-form-item>
     <el-form-item label="密码" prop="password" required>
       <el-input autocomplete="off" readonly onfocus="this.removeAttribute('readonly');" v-model="data.password"