Pull requests should go via GitHub; there are some nice general guidelines for contributing on GitHub if you haven't done it before.
Unless your fix is trivial, it's a good idea to look for related discussions and maybe open an issue to discuss, before making a pull request. Discussion in advance may keep you from wasting time on an approach that won't work out. However, if you communicate better in code than in words, starting with a patch is fine... just be willing to revise it!
Before we can accept pull requests, you will need to agree to the Typesafe Contributor License Agreement online, using your GitHub account - it takes 30 seconds. You can do this at https://www.lightbend.com/contribute/cla
Expect that most PRs will need revision before merge. If people suggest revisions, you can make them yourself or wait for a maintainer to do it on their own timeline. The larger the PR, the more revision will likely be needed.
See RELEASING.md