Add migration file for Sequelize

[eklemen]

Is your feature request related to a problem? Please describe.
No

Describe the solution you'd like
There should be at least one migration file for Sequelize option to show as example.
There should also be scripts added to npm which could shortcut to run those migrations/seeds for convenience.

Describe alternatives you've considered
Sequelize will take models and create the tables and schemas from that, so it is not necessary to have a migration file especially for bootstrapping a project. This would be optional and informational only.

Additional context
This should be compatible with the Sequelize CLI and include a .sequelizerc file to describe paths to migrations.