The following script will create a Docker container which will run SQL Server and assign a password for user 'sa' This container will mount my C:\SQL_DB directory which contains my .mdf and .ldf files, it will then make those available to my container in the /sql_data directory. I can then open SQL Server Management Studio and attach my mdf files and go nuts from there.
# pulling the latest version here, 2017-latest an example of a more specific one.
docker pull mcr.microsoft.com/mssql/server:latest
docker run -d \
-e "ACCEPT_EULA=Y" -e "SA_PASSWORD=_yourPassw0rd_" \
-p 1433:1433 \
-v C:\SQL_DB:/sql_data \
--name sql mcr.microsoft.com/mssql/server:latest