docs: describes usage of plugin

packages/medusa-plugin-restock-notification/README.md

@@ -1,24 +1,89 @@
 # medusa-plugin-restock-notification
 
-Twilio SMS / Messaging plugin.
 
-## Plugin Options
+## Usage
 
-```
-{
-  account_sid: [twilio messaging account sid] (required),
-  auth_token: [twilio massaging authentication token] (required),
-  from_number: [the number used as sender SMS],
+Install the plugin:
+
+`$ yarn add medusa-plugin-restock-notification`
+
+```js
+// medusa-config.js
+
+module.exports = {
+  ...,
+  plugins: [
+    ...,
+    `medusa-plugin-restock-notification`
+  ]
 }
 ```
 
-## Dynamic usage
+The plugin will migrate your database to include the RestockNotification entity, which consists of a variant id of a sold out item and a jsonb list of arrays that wish to be notified about restocks for the item.
 
-You can resolve the Twilio SMS service to dynamically send SMS's via Twilio.
 
-Example:
+## API endpoint
+
+The plugin exposes an endpoint to sign emails up for restock notifications:
+
+```
+POST /restock-notifications/variants/:variant_id
+
+Body
+{
+  "email": "seb@test.com"
+}
+```
+
+The endpoint responds with `200 OK` on succesful signups. If a signup for an already in stock item is attempted the endpoint will have a 400 response code.
+
+
+## Restock events
+
+The plugin listens for the `product-variant.updated` call and emits a `restock-notification.restocked` event when a variant with restock signups become available.
+
+The data sent with the `restock-notification.restocked` event is:
+```
+variant_id: The id of the variant to listen for restock events for.
+emails: An array of emails that are to be notified of restocks.
+
+e.g.
+
+{
+  "variant_id": "variant_1234567890",
+  "emails": ["seb@test.com", "oli@test.com"]
+}
+```
+
+*Note: This plugin does not send any communication to the customer, communication logic must be implemented or provided through a communication plugin.*
+
+You may use `medusa-plugin-sendgrid` to orchestrate transactional emails.
+
+
+## Usage with medusa-plugin-sendgrid
+
+Install the plugins:
+`$ yarn add medusa-plugin-restock-notification medusa-plugin-sendgrid`
 
 ```js
-const twilioSmsService = scope.resolve("twilioSmsService")
-twilioSmsService.sendSms({ to: "+4500112233", body: "Hello world!" })
+// medusa-config.js
+
+module.exports = {
+  ...,
+  plugins: [
+    ...,
+    `medusa-plugin-restock-notification`,
+    {
+      resolve: `medusa-plugin-sendgrid`,
+      options: {
+        from: SENDGRID_FROM,
+        api_key: SENDGRID_API_KEY,
+        medusa_restock_template: `d-13141234123412342314`
+      }
+    }
+  ]
+}
 ```
+
+You should set up a dynamic template in SendGrid which will be send for each of the emails in the restock notification.
+