Fiz todos os procedimentos conforme explicado no curso criei todas as classes e instalei os pacotes com as versoes 7 rc1 final porem recebo esse erro ao add-migration
PM> Add-Migration criaUsuario System.ArgumentNullException: Value cannot be null. Parameter name: configuration.ContextType at System.Data.Entity.Utilities.Check.NotNull[T](T value, String parameterName) at System.Data.Entity.Migrations.DbMigrator..ctor(DbMigrationsConfiguration configuration, DbContext usersContext, DatabaseExistenceState existenceState, Boolean calledByCreateDatabase) at System.Data.Entity.Migrations.DbMigrator..ctor(DbMigrationsConfiguration configuration) at System.Data.Entity.Migrations.Design.MigrationScaffolder..ctor(DbMigrationsConfiguration migrationsConfiguration) at System.Data.Entity.Migrations.Design.ToolingFacade.ScaffoldRunner.Run() at System.AppDomain.DoCallBack(CrossAppDomainDelegate callBackDelegate) at System.AppDomain.DoCallBack(CrossAppDomainDelegate callBackDelegate) at System.Data.Entity.Migrations.Design.ToolingFacade.Run(BaseRunner runner) at System.Data.Entity.Migrations.Design.ToolingFacade.Scaffold(String migrationName, String language, String rootNamespace, Boolean ignoreChanges) at System.Data.Entity.Migrations.AddMigrationCommand.Execute(String name, Boolean force, Boolean ignoreChanges) at System.Data.Entity.Migrations.AddMigrationCommand.<>cDisplayClass2.<.ctor>b0() at System.Data.Entity.Migrations.MigrationsDomainCommand.Execute(Action command) Value cannot be null. Parameter name: configuration.ContextType