docs: correct the scheduler guidance for Docker

docs/guide/recurring-invoices.md

@@ -46,7 +46,16 @@ In order for InvoiceShelf to automatically create Invoices on a given schedule,
 
 #### For Docker:
 
-InvoiceShelf includes support for cron with docker on version 5.0.0 by default. If you're updating from a previous version, please take a backup of your database + files and re-run `docker-compose up`.
+The InvoiceShelf image runs the scheduler itself, as a supervised service
+alongside the web server, so a container install needs no cron of its own.
+
+If your recurring invoices have never been created, update to a current image:
+earlier images shipped no scheduler at all, and nothing on this page ran.
+
+Set `SCHEDULER_ENABLED=false` only if you drive the schedule from somewhere
+else, such as a second container running
+`php artisan schedule:work` or more than one replica of the web container.
+Leave it unset otherwise.
 
 #### Other Providers:
 
@@ -62,6 +71,26 @@ Example command for a shared hosting provider like Godaddy:
  /usr/local/bin/php /home/myuser/public_html/InvoiceShelf/artisan schedule:run >> /dev/null 2>&1
 ```
 
+#### Hosts With No Cron At All:
+
+Some shared hosts allow neither a crontab entry nor a long-running process. For
+those, InvoiceShelf can be driven over HTTP: set a secret in your `.env`
+
+```
+CRON_JOB_AUTH_TOKEN=a-long-random-string
+```
+
+and have any external scheduler call the endpoint below once a minute, sending
+the secret in the `x-authorization-token` header.
+
+```
+curl -H "x-authorization-token: a-long-random-string" https://your-invoiceshelf/api/cron
+```
+
+The endpoint refuses every caller while the token is unset, so it is inert
+unless you deliberately turn it on. Calling it more often than once a minute is
+harmless: extra calls answer `{"success": true, "ran": false}` and do nothing.
+
 #### Testing Locally:
 
 Run the below command if you would like to test recurring invoices on your local machine. (Note: This command does not work on windows)

docs/install/docker.md

@@ -131,3 +131,17 @@ services in `docker-compose.yml` before making the installation public.
 
 Select SQLite and leave the database path unchanged:
 `/var/www/html/storage/app/database.sqlite`.
+
+## Scheduled work
+
+The container runs Laravel's scheduler itself, supervised alongside the web
+server. That is what creates recurring invoices, flags invoices overdue and
+expires estimates, so there is no crontab to add on the host.
+
+Set `SCHEDULER_ENABLED=false` only if you drive the schedule from elsewhere,
+for example a second container started with
+`command: ["php", "/var/www/html/artisan", "schedule:work"]`, or if you run more
+than one replica of the web container and want exactly one of them scheduling.
+
+See [Recurring Invoices](../guide/recurring-invoices.md#server-configuration)
+for the options open to hosts that can run neither.