The Entity Framework Core Package Manager Console Tools don't support PowerShell version 2.0. Upgrade to PowerShell version 3.0 or higher

I want use EF Core in Asp.net core so i follow this Instruction but when i want to use this command:Add-Migration first for creating database in PackageManger console, it gives me this error:

The Entity Framework Core Package Manager Console Tools don't support PowerShell version 2.0. Upgrade to PowerShell version 3.0 or higher, restart Visual Studio, and try again.

what is the problem?

NOTE: this is my Project.json file:

{
 "dependencies": {
   "Microsoft.NETCore.App": {
     "version": "1.0.1",
     "type": "platform"
   },
   "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": "1.1.0",
   "Microsoft.Extensions.Logging.Console": "1.0.0",
   "Microsoft.Extensions.Logging.Debug": "1.0.0",
   "Microsoft.Extensions.Options.ConfigurationExtensions": "1.0.0",
   "Microsoft.EntityFrameworkCore.SqlServer": "1.1.0",
   "Microsoft.EntityFrameworkCore.Tools": "1.1.0-preview4-final",
   "Microsoft.EntityFrameworkCore.Design": "1.1.0"
  },

  "tools": {
    "Microsoft.AspNetCore.Server.IISIntegration.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%" ]
   }
}