Development work should not be done directly on a master or release branch.
This will allow more fine grained control of what bugs make it into a particular release. Instead each bug should be fixed within its own branch. Name the branch after the open JIRA ticket so there is a relationship between the two.
Creating a bug fix branch
Completed bugs should include fixes as well as good test coverage that documents the problem. This will prevent the same thing from coming up again after code rewrites / feature changes.
Merging bug fixes
Once a bug fix is ready to be tested by team members it needs to be merged into the current release. This should be done by issuing a pull request from the same repository. For help on how to do so check Github's documentation.
The release manager will be responsible for merging the pull request into the current release branch (in this case release/1.0.0).