chore: added description to docs

packages/core/docs/.vuepress/config.js

@@ -149,7 +149,8 @@ module.exports = {
 						['/general/error-handling', 'Error Handling'],
 						['/general/logging', 'Logging'],
 						['/general/performance', 'Performance'],
-						['/general/context', 'Application Context']
+						['/general/context', 'Application Context'],
+						['/general/notifications', 'In-app Notifications']
 					]
 				},
 				{

packages/core/docs/general/notifications.md

@@ -0,0 +1,36 @@
+# In-app Notifications
+
+In Vue Storefront we're providing Notifications system based on composable `useUiNotification`. 
+
+Shows notifications after some actions being performed in the shop. There are three types of notifications: danger, success and info.
+
+There is a dedicated interface for `useUiNotification`:
+
+```ts
+interface UseUiNotification {
+  message: string;
+  type: 'danger' | 'success' | 'info';
+  action?: { text: string; onClick: Function };
+  icon?: string;
+  persist?: boolean;
+  id?: symbol;
+  dismiss?: () => void;
+}
+```
+
+### How to send notification?
+
+To send a new notification you need to only import `useUiNotification` from composables and pass `type` and `message` to `send` function. Rest parameters are optional.
+
+```js
+import { useUiNotification } from '~/composables';
+
+setup() {
+  const { send } = useUiNotification();
+
+  send({
+    type: 'success',
+    message: 'Successfully added product to the cart'
+  })
+}
+```