We automatically push tags to Rubygems via CI.

Pre-releases

Make sure you're on the latest master
Bump the version in version.rb
Update History.md
Commit these changes. git commit -am "Release x.y.z.pre"
Tag the pre-release. git tag -a -m "Version x.y.z.pre" x.y.z.pre
git push -u origin master && git push --tags. The tagged commit will be pushed to RubyGems via Travis

Promoting pre-releases

Find the tag for the pre-release you want to promote. Use git tag --list '*.pre' to list all pre-release tags
Checkout that tag. git checkout tags/x.y.z.pre
Update the version in version.rb to not include the .pre suffix
Commit these changes. git commit -am "Promote x.y.z.pre"
Tag the release. git tag -a -m "Version x.y.z" x.y.z
git push -u origin master && git push --tags. The tagged commit will be pushed to RubyGems via Travis
On master, add an entry to History.md under x.y.z that says 'Promoted pre-release to stable'