Add all the database schema migration guides

[gitbuda]

• https://github.com/liquibase/liquibase -> Add schema migration using Liquibase #54
• https://github.com/flyway/flyway -> Add schema migration using Flyway #55
• https://github.com/golang-migrate/migrate
• https://github.com/sqitchers/sqitch
• https://github.com/ariga/atlas
• https://github.com/amacneil/dbmate