asp.net core / EF-Core errore di aggiornamento del database mysql

Sono assolutamente nuovo nello sviluppo del core di asp.net. Sto cercando di creare una semplice API web asp.net con un singolo modello e mysql per archiviare i dati del modello e quindi vorrei recuperarla come API REST magari usando Swagger.

La mia attuale configurazione sembra essere la seguente:

Books.cs:

using Microsoft.EntityFrameworkCore;
using MySQL.Data.EntityFrameworkCore.Extensions;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace New_Api.Models
{
    public class Book
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string Author { get; set; }
        public decimal Price { get; set; }
        public DateTime CreatedOn { get; set; } = DateTime.UtcNow;

    }

    public class WebAPIDataContext : DbContext
    {
        public WebAPIDataContext(DbContextOptions<WebAPIDataContext> options)
            : base(options)
        {
        }
        public DbSet<Book> Books { get; set; }
    }

}

Project.json:

{
  "dependencies": {
    "Microsoft.NETCore.App": {
      "version": "1.0.1",
      "type": "platform"
    },
    "Microsoft.ApplicationInsights.AspNetCore": "1.0.0",
    "Microsoft.AspNetCore.Mvc": "1.0.1",
    "Microsoft.AspNetCore.Routing": "1.0.1",
    "Microsoft.AspNetCore.Server.IISIntegration": "1.0.0",
    "Microsoft.AspNetCore.Server.Kestrel": "1.0.1",
    "Microsoft.Extensions.Configuration.EnvironmentVariables": "1.0.0",
    "Microsoft.Extensions.Configuration.FileExtensions": "1.0.0",
    "Microsoft.Extensions.Configuration.Json": "1.0.0",
    "Microsoft.Extensions.Logging": "1.0.0",
    "Microsoft.Extensions.Logging.Console": "1.0.0",
    "Microsoft.Extensions.Logging.Debug": "1.0.0",
    "Microsoft.Extensions.Options.ConfigurationExtensions": "1.0.0",
    "Microsoft.EntityFrameworkCore": "1.0.0",
    "MySql.Data.Core": "7.0.4-IR-191",
    "MySql.Data.EntityFrameworkCore": "7.0.4-IR-191",
    "Microsoft.EntityFrameworkCore.Tools": "1.0.0-preview2-final"
  },

  "tools": {
    "Microsoft.AspNetCore.Server.IISIntegration.Tools": "1.0.0-preview2-final",
    "Microsoft.EntityFrameworkCore.Tools": "1.0.0-preview2-final"
  },

  "frameworks": {
    "netcoreapp1.0": {
      "imports": [
        "dotnet5.6",
        "portable-net45+win8"
      ]
    }
  },

  "buildOptions": {
    "emitEntryPoint": true,
    "preserveCompilationContext": true
  },

  "runtimeOptions": {
    "configProperties": {
      "System.GC.Server": true
    }
  },

  "publishOptions": {
    "include": [
      "wwwroot",
      "**/*.cshtml",
      "appsettings.json",
      "web.config"
    ]
  },

  "scripts": {
    "postpublish": [ "dotnet publish-iis --publish-folder %publish:OutputPath% --framework %publish:FullTargetFramework%" ]
  }
}

appsettings.json:

{

    "ConnectionStrings": {
      "SampleConnection": "server=localhost;userid=root;pwd=root;port=3306;database=asptest;sslmode=none;"
    },
  "Logging": {
    "IncludeScopes": false,
    "LogLevel": {
      "Default": "Debug",
      "System": "Information",
      "Microsoft": "Information"
    }
  }
}

E nel mio startup.cs:

 public void ConfigureServices(IServiceCollection services)
        {
            // Add framework services.
            services.AddApplicationInsightsTelemetry(Configuration);
            services.AddDbContext<WebAPIDataContext>(options =>
            {
                options.UseMySQL("SampleConnection");
            });

            services.AddMvc();
        }

Dopo questo molto di set up, ho ripristinato tutti i pacchetti ed eseguito le dotnet ef migrations add initial che ha creato la cartella Migrations (suppongo significhi che sia andata a buon fine). Successivamente ho eseguito l' dotnet ef database update che mi dà errore: il Format of the initialization string does not conform to specification starting at index 0

Cosa c'è che non va?