[Rails5] Ruby on Rails stub server requires MySQL but does not use it

Created by: ledsun

Description

The Ruby on Rails stub server requires MySQL. Its Gemfile includes line blew:

# Use mysql as the database for Active Record
gem 'mysql2', '>= 0.3.18', '< 0.5'

To start the Ruby on Rails stub server, we need to install MySQL in the development environment. However, the Ruby on Rails stub server does not use the database. I think this is a meaningless cost.

openapi-generator version

3.0.0

OpenAPI declaration file content or url

Any.

Command line used for generation

bin/rails5-petstore-server.sh

Steps to reproduce

bin/rails5-petstore-server.sh

Related issues/PRs

No.

Suggest a fix/enhancement

Switch the database to SQLite for Ruby on Rails stub server like: https://github.com/ledsun/openapi-generator/tree/rails_reduce_dependency

We can start the Ruby on Rails stub server in fewer steps.