The core structure of a standard Ruby project is basically:
lib/
foo.rb
foo/
share/
foo/
test/
helper.rb
test_foo.rb
HISTORY.md (or CHANGELOG.md)
LICENSE.txt
README.md
foo.gemspec
The share/ is rare and is sometimes called data/ instead. It is for general purpose non-ruby files. Most projects don't need it, but even when they do many times everything is just kept in lib/, though that is probably not best practice.
The test/ directory might be called spec/ if BDD is being used instead of TDD, though you might also see features/ if Cucumber is used, or demo/ if QED is used.
These days foo.gemspec can just be .gemspec --especially if it is not manually maintained.
If your project has command line executables, then add:
bin/
foo
man/
foo.1
foo.1.md or foo.1.ronn
In addition, most Ruby project's have:
Gemfile
Rakefile
The Gemfile is for using Bundler, and the Rakefile is for Rake build tool. But there are other options if you would like to use different tools.
A few other not-so-uncommon files:
VERSION
MANIFEST
The VERSION file just contains the current version number. And the MANIFEST (or Manifest.txt) contains a list of files to be included in the project's package file(s) (e.g. gem package).
What else you might see, but usage is sporadic:
config/
doc/ (or docs/)
script/
log/
pkg/
task/ (or tasks/)
vendor/
web/ (or site/)
Where config/ contains various configuration files; doc/ contains either generated documentation, e.g. RDoc, or sometimes manually maintained documentation; s
answered 2012-12-24T09:23:29.497