Getting users multiple users for basic auth, spring boot security

I have a list of users, and I want to use them in my basic auth.

MY code currently looks like this:

public class BasicAuthConfig extends WebSecurityConfigurerAdapter {

  public PasswordEncoder passwordEncoder(){return new BCryptPasswordEncoder();}
  private ConfigService configService;
  // Authentication : User --> Roles
  // NoOpPasswordEncoder has been deprecated in Spring security so {noop} is being used to avoid errors
  protected void configure(AuthenticationManagerBuilder auth)
    throws Exception {

  // Authorization : Role -> Access
  protected void configure(HttpSecurity http) throws Exception {

I want to replace “someuser” and “somepassword” with usernames and passwords from my list of users. Currently I can get the list with configService.getCOnfigurations().getUsers().
A user just has a username and a password, both strings. How do I go about getting all the usernames and all the passwords into .withUser()?