post for creating invite tokens in admin api

docs/api/admin_api.md

@@ -226,13 +226,25 @@ Note: Available `:permission_group` is currently moderator and admin. 404 is ret
 
 ### Get an account registration invite token
 
-- Methods: `GET`
+- Methods: `POST`
 - Params:
   - *optional* `invite` => [
     - *optional* `max_use` (integer)
     - *optional* `expires_at` (date string e.g. "2019-04-07")
   ]
-- Response: invite token (base64 string)
+- Response:
+
+```json
+{
+  "id": integer,
+  "token": string,
+  "used": boolean,
+  "expires_at": date,
+  "uses": integer,
+  "max_use": integer,
+  "invite_type": string (possible values: `one_time`, `reusable`, `date_limited`, `reusable_date_limited`)
+}
+```
 
 ## `/api/pleroma/admin/users/invites`