Update Releasing.md with API info

doc/en/Developer/Releasing.md

@@ -37,6 +37,22 @@ Unless you want to discuss something confidential with the developers, please do
 * Run code checker.
 * If needed re-build the minified Javascript (e.g. `npx grunt --root=question/type/stack`).
 
+### Check API
+
+* Spin up the STACK API in Docker and check it still works with a selection of questions, including download and JSXGraph.
+* Chances are it won't work because even the latest version of goemaxima is out of date.
+* You will need to create a local up-to-date image of goemaxima:
+  * Clone the goemaxima repo and create a folder stack/STACKVERSION e.g. `stack/2024050600` matching the latest STACK version.
+  * Copy the stack/maxima folder from STACK into this new folder.
+  * Create `maximalocal.mac.template` as described in `Adding_new_version.md` in goemaxima docs (or just copy from previous goemaxima version).
+  * In `buildimage.sh` set `maximaver` and `sbclver` e.g. `maximaver="5.45.1" sbclver="2.2.6"`. (`maximaver` should match `maximalocal.mac.template`)
+  * `./buildweb.sh` (You may need to install `go` first: `sudo snap install go --classic`).
+  * `.buildimage.s 2024050600` (If Docker struggles to fetch metadata `sudo vi ~/.docker/config.json` and change `credsStore` to `credStore`).
+  * You should have now created a `goemaxima:2024050600-dev` image locally.
+* Temporarily update STACK API locally:
+  * Update maxima image in STACK API to `goemaxima:2024050600-dev` in `docker-compose.dev.yml`.
+  * Update `stackmaximaversion` and `version` in `config.php` for the API to e.g. 2024050600.
+* `docker compose -f docker-compose.dev.yml up`
 
 ### Version numbers