Change `subscription` store property to `subscribed`

ee/app/assets/javascripts/epics/sidebar/components/sidebar_app.vue

@@ -177,13 +177,13 @@
           this.toggleSidebar();
         }
       },
-      handleToggleSubscription() {
-        this.service.toggleSubscription()
+      handleToggleSubscribed() {
+        this.service.toggleSubscribed()
           .then(() => {
-            this.store.setSubscription(!this.store.subscription);
+            this.store.setSubscribed(!this.store.subscribed);
           })
           .catch(() => {
-            if (this.store.subscription) {
+            if (this.store.subscribed) {
               Flash(__('An error occurred while unsubscribing to notifications.'));
             } else {
               Flash(__('An error occurred while subscribing to notifications.'));
@@ -260,8 +260,8 @@
       />
       <sidebar-subscriptions
         :loading="savingSubscription"
-        :subscribed="store.subscription"
-        @toggleSubscription="handleToggleSubscription"
+        :subscribed="store.subscribed"
+        @toggleSubscription="handleToggleSubscribed"
         @toggleCollapse="toggleSidebar"
       />
     </div>

ee/app/assets/javascripts/epics/sidebar/services/sidebar_service.js

@@ -14,7 +14,7 @@ export default class SidebarService {
     return axios.put(this.endpoint, { end_date: endDate });
   }
 
-  toggleSubscription() {
+  toggleSubscribed() {
     return axios.post(this.subscriptionEndpoint);
   }
 }

ee/app/assets/javascripts/epics/sidebar/stores/sidebar_store.js

@@ -15,11 +15,7 @@ export default class SidebarStore {
     return this.endDate ? parsePikadayDate(this.endDate) : null;
   }
 
-  get subscription() {
-    return this.subscribed;
-  }
-
-  setSubscription(subscribed) {
+  setSubscribed(subscribed) {
     this.subscribed = subscribed;
   }
 }

spec/javascripts/epics/sidebar/stores/sidebar_store_spec.js

@@ -54,4 +54,13 @@ describe('Sidebar Store', () => {
       expect(date.getFullYear()).toEqual(2017);
     });
   });
+
+  describe('setSubscribed', () => {
+    it('should set store.subscribed value', () => {
+      const store = new SidebarStore({ subscribed: true });
+
+      store.setSubscribed(false);
+      expect(store.subscribed).toEqual(false);
+    });
+  });
 });