Use new issue order endpoint

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

@@ -95,7 +95,7 @@ export default {
       const issueToRemove = _.find(this.state.relatedIssues, issue => issue.id === idToRemove);
 
       if (issueToRemove) {
-        this.service.removeRelatedIssue(issueToRemove.destroy_relation_path)
+        this.service.removeRelatedIssue(issueToRemove.relation_path)
           .then(res => res.json())
           .then((data) => {
             this.store.setRelatedIssues(data.issues);
@@ -164,7 +164,10 @@ export default {
       const issue = _.find(this.state.relatedIssues, issue => issue.id === issueId);
 
       if (issue) {
-        this.service.saveIssueOrder(issue.epic_issue_id, newOrder);
+        this.service.saveRelatedIssueOrder({
+          endpoint: issue.related_path,
+          position: newOrder,
+        });
       }
     },
 

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

@@ -6,7 +6,6 @@ Vue.use(vueResource);
 class RelatedIssuesService {
   constructor(endpoint) {
     this.relatedIssuesResource = Vue.resource(endpoint);
-    this.reorderIssuesResource = Vue.resource(`${endpoint}{/id}/order`);
   }
 
   fetchRelatedIssues() {
@@ -19,11 +18,11 @@ class RelatedIssuesService {
     });
   }
 
-  saveIssueOrder(issueId, position) {
-    return this.reorderIssuesResource.update({
-      id: issueId,
-    }, {
-      position,
+  saveRelatedIssueOrder({ endpoint, position }) {
+    return Vue.http.put(endpoint, {
+      epic: {
+        position,
+      },
     });
   }