Add reorder service on frontend

app/assets/javascripts/issuable/related_issues/components/related_issues_block.vue

@@ -96,6 +96,8 @@ export default {
     reordered(event) {
       this.removeDraggingCursor();
       console.log(event);
+
+      this.$emit('saveReorder', event);
     },
     addDraggingCursor() {
       document.body.classList.add('is-dragging');

app/assets/javascripts/issuable/related_issues/components/related_issues_root.vue

@@ -160,6 +160,9 @@ export default {
           Flash('An error occurred while fetching issues.');
         });
     },
+    saveIssueOrder() {
+      this.service.saveIssueOrder(1, 1);
+    },
 
     onInput(newValue, caretPos) {
       const rawReferences = newValue
@@ -239,5 +242,6 @@ export default {
     :input-value="inputValue"
     :auto-complete-sources="autoCompleteSources"
     :title="title"
+    @saveReorder="saveIssueOrder"
   />
 </template>

app/assets/javascripts/issuable/related_issues/services/related_issues_service.js

@@ -6,6 +6,7 @@ Vue.use(vueResource);
 class RelatedIssuesService {
   constructor(endpoint) {
     this.relatedIssuesResource = Vue.resource(endpoint);
+    this.reorderIssuesResource = Vue.resource(`${endpoint}{/id}/order`);
   }
 
   fetchRelatedIssues() {
@@ -18,6 +19,14 @@ class RelatedIssuesService {
     });
   }
 
+  saveIssueOrder(issueId, position) {
+    return this.reorderIssuesResource.save({
+      id: issueId,
+    }, {
+      position,
+    });
+  }
+
   // eslint-disable-next-line class-methods-use-this
   removeRelatedIssue(endpoint) {
     return Vue.http.delete(endpoint);