Startup.cs

        public void ConfigureServices(IServiceCollection services)
        {
            const string connectionString = @"Data Source=IdentityServer.db;";
            var migrationsAssembly = typeof(Startup).GetTypeInfo().Assembly.GetName().Name;

            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);

            services.AddDbContext<ApplicationDbContext>(builder =>
                builder.UseSqlite(connectionString, sqlOptions => sqlOptions.MigrationsAssembly(migrationsAssembly)));

            services.AddIdentity<IdentityUser, IdentityRole>()
                .AddEntityFrameworkStores<ApplicationDbContext>();

            services.AddIdentityServer()
                //Configures EF implementation of IPersistedGrantStore with IdentityServer.    
                .AddOperationalStore(options =>
                    options.ConfigureDbContext = builder =>
                        builder.UseSqlite(connectionString, sqlOptions => sqlOptions.MigrationsAssembly(migrationsAssembly)))
                //Configures EF implementation of IPersistedGrantStore with IdentityServer.   
                .AddConfigurationStore(options =>
                    options.ConfigureDbContext = builder =>
                        builder.UseSqlite(connectionString, sqlOptions => sqlOptions.MigrationsAssembly(migrationsAssembly)))
                .AddAspNetIdentity<IdentityUser>()
                .AddDeveloperSigningCredential();
        }