Usually when working with ASP.Net Identity all the necessary components are added with the existing project scaffolding, but recently I needed to add an Identity database to an existing project. Below is simple way to accomplish this.

Step 1 – Install NuGet packages

From the Package Manager Console run:

Install-Package Microsoft.AspNet.Identity.EntityFramework

(this will install AspNet.Identity.Core as well)

Step 2 – Create Context Class

Create a new empty Entity Framework Code First context.   Replace the default class definition with:

...
 using Microsoft.AspNet.Identity;
 using Microsoft.AspNet.Identity.EntityFramework;

 public class SecurityDbContext : IdentityDbContext<IdentityUser>
 {
...

Update your web.config file to point the new context to a valid SQL Database.

note – If your context class overrides OnModelCreating, make sure base.OnModelCreating() is called

Step 3 – Enable Migrations & Populate Seed Method

In Package Manager Console run:

Enable-Migrations -EnableAutomaticMigrations

Then, optionally, you can create additional users or roles as needed in \Migrations\Configurations.cs:

protected override void Seed(MyApplication.Models.SecurityDbContext context)
 {
 var um = new UserManager<IdentityUser>(new UserStore<IdentityUser>(context));

 var user = new IdentityUser()
 {
 UserName = "admin"
 };

 IdentityResult ir = um.Create(user, "1234#abcD");

 }

Step 4 – Update Database

In Package Manger Console run

Update-Database

The Identity tables should now exist in the database: