Add initial blurb about Gherkin tests

[dnnrly]

Description

This shows how to perform Gherkin/Cucumber based testing.

Fixes #4

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• Running existing tests
• Created new tests

Checklist:

• My code has been linted
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing tests pass locally with my changes (buffalo test)
• I have rebased my branch to include the latest changes from main