Flesh out manual test

Author: jovial

README.md

@@ -21,7 +21,19 @@ docker run -e TANG_LISTEN_PORT=1234 -d --network host -v tang-db:/var/db/tang gh
 
 ## Manual testing
 
+This could be the basis of a CI job, but for now, outline the manual steps.
+
 ```
+# Optionally build your own container
+docker build -t ghcr.io/stackhpc/tang:latest .
+# Start a tang container
+docker run --rm -e TANG_LISTEN_PORT=1234 --name tang -d --network host -v tang-db:/var/db/tang ghcr.io/stackhpc/tang:latest
+# Encrypt some text
 echo "Hello World" | clevis encrypt tang '{ "url": "http://localhost:1234"}' > secret.jwe
+# Stop docker to trigger container deletion
+docker stop tang
+# Recreate to test persistence of DB
+docker run --rm -e TANG_LISTEN_PORT=1234 --name tang -d --network host -v tang-db:/var/db/tang ghcr.io/stackhpc/tang:latest
+# Attempt decrypt
 clevis decrypt < secret.jwe
 ```