add upgrade guide for 1.3.0

docs/content/advanced/backend/upgrade-guides/1-3-0.md

@@ -0,0 +1,43 @@
+# v1.3.0
+
+Version 1.3.0 of Medusa introduces new features to Medusa as well as prepares for a more important update to version 1.3.1.
+
+This version introduces a change in loading environment variables into your Medusa server.
+
+## Environment Variables
+
+In previous versions of Medusa, The server automatically loads all environment variables in the `.env` file at the root of the Medusa server.
+
+This new update removes loading it automatically and gives developers the freedom in how to load their environment variables. All environment variables will be loaded by default from the system’s environment variables.
+
+### Actions Required
+
+If you use a `.env` file to load environment variables on your server, you need to load the variables manually in `medusa-config.js`.
+
+You can add the following code snippet at the top of the file which uses the [dotenv](https://www.npmjs.com/package/dotenv) package to load the environment variables based on the current Node environment:
+
+```jsx
+const dotenv = require('dotenv')
+
+ let ENV_FILE_NAME = '';
+ switch (process.env.NODE_ENV) {
+  case 'production':
+    ENV_FILE_NAME = '.env.production';
+    break;
+  case 'staging':
+    ENV_FILE_NAME = '.env.staging';
+    break;
+  case 'test':
+    ENV_FILE_NAME = '.env.test';
+    break;
+  case 'development':
+  default:
+    ENV_FILE_NAME = '.env';
+    break;
+ }
+
+ try {
+  dotenv.config({ path: process.cwd() + '/' + ENV_FILE_NAME });
+ } catch (e) {
+ }
+```

www/docs/sidebars.js

@@ -214,6 +214,11 @@ module.exports = {
               label: 'Upgrade Guides',
               collapsed: true,
               items: [
+                {
+                  type: "doc",
+                  id: "advanced/backend/upgrade-guides/1-3-0",
+                  label: "v1.3.0"
+                },
                 {
                   type: "doc",
                   id: "advanced/backend/upgrade-guides/1-3-1",