Support set post sort.

src/views/system/Installation.vue

@@ -91,7 +91,7 @@
                 <a-input
                   v-model="installation.password"
                   type="password"
-                  placeholder="用户密码"
+                  placeholder="用户密码（8-100位）"
                   v-decorator="[
                     'password',
                     {rules: [{ required: true, message: '请输入密码（8-100位）' }]}

src/views/system/OptionForm.vue

@@ -116,6 +116,16 @@
                 <a-icon type="form" />文章设置
               </span>
               <a-form layout="vertical">
+                <a-form-item
+                  label="首页文章排序："
+                  :wrapper-col="wrapperCol"
+                >
+                  <a-select v-model="options.post_index_sort">
+                    <a-select-option value="createTime">创建时间</a-select-option>
+                    <a-select-option value="editTime">最后编辑时间</a-select-option>
+                    <a-select-option value="visits">点击量</a-select-option>
+                  </a-select>
+                </a-form-item>
                 <a-form-item
                   label="首页显示条数："
                   :wrapper-col="wrapperCol"