Update the initial setup files

[rica213]

The initial setup is outdated which caused some issues.

Here is the list of fixes I add:

• Update the Ruby version to 3.2.2 (because this is the version I am using).
• Add an extra step to the instruction, on how to update the Ruby version.
• Update factory_girl to factory_bot, because factory_girl is deprecated.
• Fix migration issue: directly inheriting from ActiveRecord::Migration is not supported.

[diogolsq]

Thanks for that @rica213