Database initialization in Docker.md

Put init db .sql file in designated directory.

• For MySql: /docker-entrypoint-initdb.d/
  • See: docker-library/postgres#193 (comment)
• For PostgreSql: /docker-entrypoint-initdb.d/
  • See: https://medium.com/@wkrzywiec/database-in-a-docker-container-how-to-start-and-whats-it-about-5e3ceea77e50
• For MS SQL Server:
  • 😕 microsoft/mssql-docker#11
  • 😕 https://www.abhith.net/blog/create-sql-server-database-from-a-script-in-docker-compose/
    • Hopefully, we'll get something like this built into the SQL Server engine and configurable via an env variable (MSSQL_STARTUP_SCRIPTS_DIR or something) in a future release, but for now, this is a good way to handle it. [microsoft/mssql-docker#11 (comment)] Why Microsft? Why? 😫😫😫