Docker secrets passing as environment variable
You are misunderstanding the concept of docker secrets.The whole point of creating secrets is avoiding putting sensitive information into environment variables.
In your example the PASSWORD environment variable will simply carry the value /run/secrets/password which is a file name and not the password admin.
A valid usacase of docker secrets would be, that your docker-image reads the password from that file.Checkout the docs here especially the example about MySQL:
the environment variables MYSQL_PASSWORD_FILE and MYSQL_ROOT_PASSWORD_FILE to point to the files /run/secrets/mysql_password and /run/secrets/mysql_root_password. The mysql image reads the password strings from those files when initializing the system database for the first time.
In short: your docker image should read the content of the file /run/secrets/password