Database Migration to Manage App

[ProgramadorDeValor]

As explained in the issue #196 . This is the pull request that implements it.

• It's a possible breaking change, that's why I put 2.6.0
• Won't change any environment variables that already exists.
• the .env it's created automatically to fit the needs of db-migrate module. Not necessary any aditional config.
• updated dockerfiles to install db-migrate as global.
• the migrations uses the original sql, but were organized in a different way to allow a better visualization and maintenance
• Migration Up and Down were tested.

[paschmann]

Thanks for the contribution, going to close this request due to recent changes.