Docs: Add documentation (or command) for running test SAML server

[kadamwhite]

When developing this plugin, we need to be able to run a SAML provider to validate and test the WordPress plugin properly integrates with the authentication provider.

This shell command has been provided by the Altis team as a way to spin up a local identify provider:

    docker run --name=localsaml \
        -p 8086:8080 \
        -p 8443:8443 \
        -e SIMPLESAMLPHP_SP_ENTITY_ID=https://<your-local-wordpress-url>/ \
        -e SIMPLESAMLPHP_SP_ASSERTION_CONSUMER_SERVICE=https://<your-local-wordpress-url>/sso/verify \
        -e SIMPLESAMLPHP_SP_SINGLE_LOGOUT_SERVICE=https://<your-local-wordpress-url>/sso/logout \
        -d --rm kristophjunge/test-saml-idp

Warning

This docker container is not build for Apple Silicon. If using Docker Desktop, you need to be using the Apple Virtualization Framework and need Rosetta enabled.

Notes

• The trailing slash on the entity ID is required