feat: Add register command for auto-generating model registry

[DivineUX23]

Description:

This pull request introduces a new register command to the migration tool. This feature significantly improves the user experience by automating the creation and maintenance of the models_registry.go file.

The Problem

Previously, users had to manually create the models_registry.go file and add every GORM model to the ModelTypeRegistry map. This process was tedious, error-prone, and difficult to keep in sync as a project's models evolved.

The Solution

The new register command solves this problem by:

• Scanning a specified directory (or the models/ directory by default) for .go files.
• Using Go's Abstract Syntax Tree (AST) parser to find all structs that embed gorm.Model.
• Dynamically generating a models_registry.go file populated with all discovered models.

This automation removes a manual step, reduces the chance of human error, and makes the tool much easier to adopt and use.

How to Use

To generate the model registry, a user can now simply run:

go run cmd/migration/main.go register [path/to/your/models]

Key Changes

• migration/commands/register.go: Added the new register cobra command.
• migration/commands/utils.go: Implemented the core logic (createModelRegisterFile, getModels, modelPerser) for finding model files, parsing them with AST, and generating the registry file content.
• README.md: Updated the documentation to reflect the new, simplified workflow and explain how to use the register command.

This change makes the initial setup and ongoing maintenance for users of this library much simpler and more robust.

[beesaferoot]

Thanks for the PR @DivineUX23 will have a look

[beesaferoot]

🪄 This is really cool. Thank you. 👍🏾

I added a few comments