fix(leaderboard): add missing Leaderboard#destroy

Author: leeyeh

src/leaderboard.js

@@ -321,5 +321,17 @@ _.extend(
         authOptions,
       }).then(data => this._finishFetch(data));
     },
+    /**
+     * (masterKey required) Delete the Leaderboard and its all archived versions.
+     * @param {AuthOptions} [authOptions]
+     * @return {void}
+     */
+    destroy(authOptions) {
+      return AV.request({
+        method: 'DELETE',
+        path: `/leaderboard/leaderboards/${this.statisticName}`,
+        authOptions,
+      }).then(() => undefined);
+    },
   }
 );

storage.d.ts

@@ -847,6 +847,7 @@ export class Leaderboard {
     authOptions?: AuthOptions
   ): Promise<Leaderboard>;
   reset(authOptions?: AuthOptions): Promise<Leaderboard>;
+  destroy(authOptions?: AuthOptions): Promise<void>;
 }
 
 export enum LeaderboardOrder {

test/leaderboard.js

@@ -150,13 +150,7 @@ describe('Leaderboard', () => {
     });
   });
 
-  after(() =>
-    AV.request({
-      method: 'DELETE',
-      path: `/leaderboard/leaderboards/${statisticName}`,
-      authOptions: {
-        useMasterKey: true,
-      },
-    })
-  );
+  after(function() {
+    return this.leaderboard.destroy({ useMasterKey: true });
+  });
 });