add addon actions

src/content/reducers/addon.js

@@ -0,0 +1,24 @@
+import actions from 'content/actions';
+
+const defaultState = {
+  enabled: true,
+};
+
+export default function reducer(state = defaultState, action = {}) {
+  switch (action.type) {
+  case actions.ADDON_ENABLE:
+    return Object.assign({}, state, {
+      enabled: true,
+    });
+  case actions.ADDON_DISABLE:
+    return Object.assign({}, state, {
+      enabled: false,
+    });
+  case actions.ADDON_TOGGLE_ENABLED:
+    return Object.assign({}, state, {
+      enabled: !state.enabled,
+    });
+  default:
+    return state;
+  }
+}