ruby gems vs rails gems
Sorry if this is a newbie question but what exactly is the difference between the gem structure of a Ruby gem vs. Rails gem.
Strictly speaking, all Rails gems are also Ruby gems, but not the other way around. So what additional files are required to make a ruby gem into a Rails gem.
For example, in this post, Building a ruby gem for Rails applications, the top answer suggests that all Rails gems need an init.rb. But then I found some rails gems that don't have the init.rb file. Here is an example: https://github.com/collectiveidea/awesome_nested_set
Basically, I want to write a Rails gem. I find a lot of tutorials on writing Ruby gems, but I just want to make sure it works for a Rails app.
To put it simply, rails IS a ruby gem. A ruby gem is a ruby gem, and some are just built specifically for use with rails.
It's worth noting that gems and plugins are different, and you might be confusing the two: