***Important:** Upgrading from a previous version of RavenDB.Identity? See <a href="#updating-from-old-version">Updating From Old Version</a> for steps to migrate to the latest RavenDB.Identity.*
1. Add an [AppUser class](https://github.com/JudahGabriel/RavenDB.Identity/blob/master/Sample/Models/AppUser.cs) that derives from Raven.Identity.IdentityUser:
4. In your controller actions, [call .SaveChangesAsync() when you're done making changes](https://github.com/JudahGabriel/RavenDB.Identity/blob/master/Sample/Filters/RavenSaveChangesAsyncFilter.cs#L35). Typically this is done via a RavenController base class for MVC/WebAPI projects or via an action filter. See our sample [RavenSaveChangesAsyncFilter.cs](https://github.com/JudahGabriel/RavenDB.Identity/blob/master/Sample/Filters/RavenSaveChangesAsyncFilter.cs).
## <a id="updating-from-old-version">Updating From Old Version of RavenDB.Identity</a>
Using an old version of RavenDB.Identity and want to upgrade to the latest? You need to call the `MigrateToV6` method:
```csharp
// Update our existing users to the latest RavenDB.Identity v6.
// This is necessary only if you stored users with a previous version of RavenDB.Identity.
// Failure to call this method will result in existing users not being able to login.
// This method can take several minutes if you have thousands of users.
UserStore<AppUser>.MigrateToV6(docStore)
```
This upgrade step is necessary because we [updated RavenDB.Identity to use RavenDB's cluster-safe compare/exchange](https://github.com/JudahGabriel/RavenDB.Identity/issues/5) to enforce user name/email uniqueness.
Previous versions of RavenDB.Identity had relied on `IdentityUserByUserName` IDs to enforce uniqueness, but this isn't guaranteed to work in a cluster. Calling MigrateToV6 will create compare/exchange values in Raven for each email address, and will remove the now-obsolete IdentityUserByUserNames collection.