Where to put Gradle configuration (i.e. credentials) that should not be committed?

I’m trying to deploy a Gradle-built artifact to a Maven repo, and I need to specify credentials for that. This works fine for now:

uploadArchives {
    repositories {
        mavenDeployer {
            repository(url: "http://.../nexus/content/repositories/snapshots/") {
                authentication(userName: "admin", password: "admin123")
            }
        }
    }
}

But I don’t like having to store the credentials in source control. With Maven, I would define a server configuration, and assign credentials in my ~/.m2/settings.xml. How do I do something similar with Gradle?