Add support for flash messages utilizing redux

resources/scripts/redux/reducers.ts

@@ -0,0 +1,7 @@
+import { combineReducers } from 'redux';
+import flashReducer from './reducers/flash';
+import { ReduxState } from '@/redux/types';
+
+export const reducers = combineReducers<ReduxState>({
+    flashes: flashReducer,
+});