How to make RavenDB DocumentStore available to calling APIs

I have an MVC4 application using RavenDB as a datastore. The application has MVC/Web, Domain, Data, and Security layers.

I am writing custom membership and role providers that need to initialize the database and access the DocumentStore. I'm writing these class from the Security layer, and would like to use a singleton DocumentStore (set in the application), but I can't figure out how to access it.

Other, examples I see of writing custom providers for RavenDB create new DocumentStore instances within the Provider.Initialize() methods, but that seems to break the rule of having a single DocumentStore per server.

Currently, I create a single instance of the RavenDB DocumentStore in Application_Start(). I have a base controller in the MVC/Web layer that handles the DocumentStore.Session(s).

Is there a way of accomplishing this? Should I move my security logic into the MVC/Web layer to simplify things?

I came up with my own solution using a singleton pattern.

What I did was create a singleton, that exposes a public IDocumentStore property, in the data layer of my application. It utilizes a static constructor which runs upon first request for static property (executed in Application_Start), and in turn instantiates an IDocumentStore object. The initial instance is then then returned for each reference to DocStore.Instance in a base controller and in other layers of my application (like the security layer f.ex.)

public sealed class DocStore
{
    protected static readonly IDocumentStore instance;

    static DocStore()
    {
        // instantiate documentStore
        instance = new DocumentStore { ConnectionStringName = Constants.ConnectionStrings.XXXXX };
        instance.Initialize();

        // instantiate tenants
        try
        {
            instance.DatabaseCommands.EnsureDatabaseExists(Constants.Tenants.XXXXX);
        }
        catch (Exception ex)
        {

            //TODO: catch exception
            throw ex;
        }

        // initialize indexed
        try
        {
            InitializeIndexes(instance);
        }
        catch (Exception ex)
        {

            //TODO: catch exception
            throw ex;
        }
    }

    private DocStore()
    {

    }

    public static IDocumentStore Instance
    {
        get { return instance; }
    }

    private static void InitializeIndexes(IDocumentStore store)
    {
        // builds all indexes defined in XXXXX.Data.dll
        var dataCatalog = new CompositionContainer(new AssemblyCatalog(typeof(DocStore).Assembly));
        IndexCreation.CreateIndexes(dataCatalog,
                                    store.DatabaseCommands.ForDatabase(Constants.Tenants.XXXXX),
                                    store.Conventions);
    }
}