Adding Caching Adapter, allows caching of _Role and _User queries (fixes #168) (#1664)

* Adding Caching Adapter, allows caching of _Role and _User queries.

src/cache.js

@@ -1,35 +1,4 @@
-/** @flow weak */
+import {InMemoryCache} from './Adapters/Cache/InMemoryCache';
 
-export function CacheStore<KeyType, ValueType>() {
-  let dataStore: {[id:KeyType]:ValueType} = {};
-  return {
-    get: (key: KeyType): ValueType => {
-      return dataStore[key];
-    },
-    set(key: KeyType, value: ValueType): void {
-      dataStore[key] = value;
-    },
-    remove(key: KeyType): void {
-      delete dataStore[key];
-    },
-    clear(): void {
-      dataStore = {};
-    }
-  };
-}
-
-const apps = CacheStore();
-const users = CacheStore();
-
-//So far used only in tests
-export function clearCache(): void {
-  apps.clear();
-  users.clear();
-}
-
-export default {
-  apps,
-  users,
-  clearCache,
-  CacheStore
-};
+export var AppCache = new InMemoryCache({ttl: NaN});
+export default AppCache;