Volunteers should be able to email you. They may also leave comments on GitHub for each issue. In some circumstances, you may even setup a Confluence page where your issues live, and let anyone make comments to that page. Communication with volunteers about the projects, how their code changes are being integrated, and how their contributions are helping your organization are all-important to keep morale and retention high.
Confluence is another Atlassian product that works with JIRA to serve as an informational wiki. Your projects could be listed on Confluence, and depending on your communication preferences, users should be able to leave comments on projects while they work on them.
One way we track volunteers on GitHub is by creating a specific repository called allianceTime that has a basic Readme file in it which indicates whether or not an individual is available each quarter. We ask volunteers to fork this repository and update the text document with their own schedule. This system allows you to automatically know which of your volunteers are familiar with GitHub, let’s them self-report how much time they have to contribute each quarter, and creates an automatic opt-out system - if they want to take a break from the community; all they have to do is unfork the repository.
CMS Systems such as Salesforce
Salesforce is rather common so we’re including that here. With CMS systems you can track volunteer hours, their contact information, skills, links, and any notes about conversations you’ve had with them or others. A great thing to include in a volunteer profile is their specific coding experience, attachments to their resume, and social topics that they may be passionate about.
Volunteers in open source are often asked to work independently. Even when a team of volunteers is tasked to work on a project together, many times an individual will be required to complete hours of work alone. Thus, it's important to give volunteer regular praise and general feedback about their participation.
There are a number of ways to do this, but the most common tools include: