Users and roles init

config.xml

<pipelines>
  <initialize>
    ...
    <processor type="SampleSite.RolesInitializer, SampleSite">
    <processor type="SampleSite.UsersInitializer, SampleSite">
    ...
  </initialize>
</pipelines>

RolesInitializer.cs

namespace SampleSite
{
    using System.Linq;
    using System.Web.Security;

    using Sitecore.Diagnostics;
    using Sitecore.Pipelines;
    using Sitecore.Security.Accounts;

    public class RolesInitializer
    {
        public const string ContentContentEditorRole = @"sitecore\sample_content_editor";

        private const string SitecoreAuthorRole = @"sitecore\Author";

        private const string SitecoreClientPublishingRole = @"sitecore\Sitecore Client Publishing";

        private const string SitecoreDesignerRole = @"sitecore\Designer";

        public virtual void Process(PipelineArgs args)
        {
            Assert.ArgumentNotNull(args, "args");

            Assert.IsTrue(Role.Exists(SitecoreAuthorRole), SitecoreAuthorRole + " is missing");
            Assert.IsTrue(Role.Exists(SitecoreDesignerRole), SitecoreDesignerRole + " is missing");
            Assert.IsTrue(Role.Exists(SitecoreClientPublishingRole), SitecoreClientPublishingRole + " is missing");

            this.CreateRole(ContentContentEditorRole, SitecoreDesignerRole, SitecoreAuthorRole, SitecoreClientPublishingRole);
        }

        protected virtual void CreateRole(string name, params string[] args)
        {
            // check & create content_editor role
            if (!Role.Exists(name))
            {
                Roles.CreateRole(name);
            }

            if (args != null && args.Length > 0)
            {
                foreach (var s in args.Where(s => !RolesInRolesManager.IsRoleInRole(Role.FromName(name), Role.FromName(s), false)))
                {
                    RolesInRolesManager.AddRoleToRole(Role.FromName(name), Role.FromName(s));
                }
            }
        }
    }
}