Postgres

Dump a Postgres database that is in a Docker container

docker exec -u <container_user> <container_name> <pg_dump> <db_name> > `date %y%m%d`_dump.sql

Restore a Postgres database that is in a Docker container

cat your_dump.sql | docker exec -i your-db-container psql -U postgres

Push a Postgres Database to Heroku Postgres

heroku pg:reset
heroku pg:push <local_db> <remote_db> --app <app_name>

(https://devcenter.heroku.com/articles/heroku-postgresql#pg-push-and-pg-pull)