feat: ✨ Add new Migration extension

.vitepress/config.mts

@@ -130,6 +130,7 @@ export default defineConfig({
                     },
                     { text: "Events", link: "/extensions/events" },
                     { text: "Reports", link: "/extensions/reports" },
+                    { text: "Migration", link: "/extensions/migration" },
                     { text: "Vanity", link: "/extensions/vanity" },
                     {
                         text: "Interactivity",

docs/extensions/migration.md

@@ -0,0 +1,47 @@
+# Migration
+
+Sometimes, users may wish to move from one instance to another. This could be due to a change in administration, a desire to be closer to friends, or any other reason. This document outlines an extension to make the process of moving instances easier.
+
+## User migrations
+
+The following object is used to represent a user migration:
+
+```json5
+{
+    "id": "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
+    "type": "Extension",
+    "extension_type": "org.lysand:migration/Migration",
+    "author": "https://example.com/users/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
+    "uri": "https://example.com/actions/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
+    "created_at": "2021-01-01T00:00:00.000Z",
+    "destination": "https://otherinstance.social/users/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
+}
+```
+
+### Fields
+
+#### Author
+
+| Name   | Type | Required |
+| :----- | :--- | :------- |
+| author | URI  | Yes      |
+
+URI of the [Actor](../objects/actors) who initiated the action. This Actor will be the user migrating.
+
+#### Destination
+
+| Name        | Type | Required |
+| :---------- | :--- | :------- |
+| destination | URI  | Yes      |
+
+URI of the user's new account.
+
+### Implementation
+
+When an instance receives a `Migration` object, the client **SHOULD** display a notification to all followers of the migrating user. This notification **SHOULD** include a link to the user's new account.
+
+Furthermore, all following relationships of the migrating user **SHOULD** be transferred to the new account. This includes followers, following, and any other relationship that may exist. The old account **SHOULD** be marked as inactive and display a message indicating that the user has migrated to a new account.
+
+#### Server Actors
+
+If the user in question is a server actor, then it should be considered that the entire instance is migrating to a new address. In this case, the above process should be applied to all users on the instance.