add global find keyword

src/background/reducers/index.js

@@ -1,12 +1,15 @@
 import settingReducer from './setting';
+import findReducer from './find';
 
 // Make setting reducer instead of re-use
 const defaultState = {
   setting: settingReducer(undefined, {}),
+  find: findReducer(undefined, {}),
 };
 
 export default function reducer(state = defaultState, action = {}) {
   return Object.assign({}, state, {
     setting: settingReducer(state.setting, action),
+    find: findReducer(state.find, action),
   });
 }