Remove mock code from approvalsApi, init SubbableResource.

app/assets/javascripts/merge_request_widget/approvals/services/approvals_api.js.es6

 //= require ../stores/approvals_store
+//= require subbable_resource
 
-// TODO: Determine whether component-specific store should be accessed here as a member
-
-((MergeRequestWidget) => {
-
-  function mockApprovalRequest(payload) {
-    const store = gl.MergeRequestWidget.Store;
-
-    return new Promise((resolve) => {
-      const approvalsStore = store.data.approvals;
-
-      setTimeout(() => {
-        resolve(approvalsStore);
-      }, 100);
-    });
-  }
-
+(() => {
   class ApprovalsApi {
     constructor() {
+      this.resource = gl.ApprovalsResource = new gl.SubbableResource('my/endpoint');
       this.store = gl.MergeRequestWidget.ApprovalsStore;
-      this.isFetching = false;
-      this.hasBeenFetched = true;
     }
 
     fetchApprovals() {
-      const payload = {
-        type: 'GET',
-      };
-      return this.genericApprovalRequest(payload);
+      return this.resource.get();
     }
 
     approveMergeRequest() {
-      const payload = {
-        type: 'POST',
-      };
-      return this.genericApprovalRequest(payload).then(() => {
+      return this.resource.post().then(() => {
         gl.MergeRequestWidget.ApprovalsStore.approve();
       });
     }
 
     unapproveMergeRequest() {
-      const payload = {
-        type: 'DELETE',
-      };
-      return this.genericApprovalRequest(payload).then(() => {
+      return this.resource.delete().then(() => {
         gl.MergeRequestWidget.ApprovalsStore.unapprove();
       });
     }
 
-    genericApprovalRequest(payload = {}) {
-      return mockApprovalRequest(payload)
-        .then(resp => this.updateStore(resp))
-        .catch((err) => {
-          throw err;
-        });
-    }
-
     updateStore(newState = {}) {
-      this.store = gl.MergeRequestWidget.Store.data.approvals; // Always update shared store
+      this.store = gl.MergeRequestWidget.Store.data.approvals;
       return Object.assign(this.store, newState);
     }
 
   }
   gl.MergeRequestWidget.ApprovalsApi = new ApprovalsApi();
-})(gl.MergeRequestWidget || (gl.MergeRequestWidget = {}));
+})();