Entity Framework

Ola pessoal boa tarde, Gostaria de uma ajuda, criei um projeto similar ao do curso, e estou com o seguinte erro, por favor podem me orientar ?

Segue o erro:

Severity    Code    Description    Project    File    Line    Suppression State
Error    CS0246    The type or namespace name 'DbContextOptionsBuilder' could not be found (are you missing a using directive or an assembly reference?)    ProjLocadora    c:\users\diogo paes\documents\visual studio 2015\Projects\ProjLocadora\ProjLocadora\LocadoraContext.cs    12    Active

Severity    Code    Description    Project    File    Line    Suppression State
Error    CS0115    'LocadoraContext.OnConfiguring(DbContextOptionsBuilder)': no suitable method found to override    ProjLocadora    c:\users\diogo paes\documents\visual studio 2015\Projects\ProjLocadora\ProjLocadora\LocadoraContext.cs    12    Active

Severity    Code    Description    Project    File    Line    Suppression State
Error    CS1674    'LocadoraContext': type used in a using statement must be implicitly convertible to 'System.IDisposable'    ProjLocadora    c:\users\diogo paes\documents\visual studio 2015\Projects\ProjLocadora\ProjLocadora\Program.cs    28    Active

Severity    Code    Description    Project    File    Line    Suppression State
Error    CS1061    'LocadoraContext' does not contain a definition for 'SaveChanges' and no extension method 'SaveChanges' accepting a first argument of type 'LocadoraContext' could be found (are you missing a using directive or an assembly reference?)    ProjLocadora    c:\users\diogo paes\documents\visual studio 2015\Projects\ProjLocadora\ProjLocadora\Program.cs    32    Active

Segue o código:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ProjLocadora
{
    class Program
    {
        static void Main(string[] args)
        {
            GravarUsandoEntity();
        }

        private static void GravarUsandoEntity()
        {

            Cliente c = new Cliente();
            c.nome = "Jose MAria";
            c.cpf = "12312345612";
            c.dataNasc = new DateTime (17,03,1987);
            c.endereco = "Rua: jose da couves";
            c.telefone = "44441111";
            c.telefone2 = "12331111";


            using (var contexto = new LocadoraContext())
            {

                contexto.Clientes.Add(c);
                contexto.SaveChanges();

                Console.Write("Por favor aperte qualquer tecla para cotinuar");
                Console.ReadKey();
            }
        }
    }
}