add ability to change the sort column

doc/en/details/props-columns.md

@@ -9,6 +9,7 @@ These are the properties of `columns[i]`:
 | field | Field name of the row | String | - | - | N |
 | explain | Explanation of the field (tooltip) | String | - | - | N |
 | sortable | Is sortable | Boolean | true / false | false | N |
+| sortField | Field to use for sorting if different than field. | String | - | - | N |
 | visible | Is visible | Boolean / String (if the type is String, the visibility is not allowed to toggle) | true / false / 'true' / 'false' | true | N |
 | fixed | Is fixed | Boolean / String | true / false / 'left' / 'right' | - | N |
 | group | Group name | String | - | - | N |

examples/dist/index.html

@@ -12,5 +12,5 @@
 
 <script src="//unpkg.com/jquery@2.1.4/dist/jquery.min.js"></script>
 <script src="//unpkg.com/bootstrap@3.3.5/dist/js/bootstrap.min.js"></script>
-<script type="text/javascript" src="client.e34add27.js"></script></body>
+<script type="text/javascript" src="client.914ee790.js"></script></body>
 </html>

src/Table/TableHeader.vue

@@ -21,7 +21,7 @@
         </template>
 
         <i v-if="col.explain" class="fa fa-info-circle" style="cursor: help" :title="col.explain"></i>
-        <head-sort v-if="col.sortable" :field="col.field" :query="query" />
+        <head-sort v-if="col.sortable" :field="col.sortField || col.field" :query="query" />
       </th>
     </transition-group>
   </thead>
@@ -35,6 +35,6 @@ import shouldRenderSelection from '../_mixins/shouldRenderSelection'
 export default {
   name: 'TableHeader',
   components: { HeadSort, MultiSelect },
-  mixins: [props, shouldRenderSelection]
+  mixins: [props, shouldRenderSelection],
 }
 </script>