new and improved example code

[jjb]

This is an example minimal app based off of this blog post:

https://www.techcareerbooster.com/blog/use-activerecord-in-your-ruby-project

It demonstrates:

• database configuration
• a migration
• a model
• loading all relevant code into a runtime and using it

Let me know what you think!

addresses #162

[jjb]

@thuss i think this is ready now

[thuss]

Looks good, thanks for the PR, merged!