I am creating a new ASP.NET Core project using dotnet 4.5.2 and am trying to add a reference to Microsoft.EntityFrameworkCore.Tools. In my project.json file I have these listed under dependencies:

```
 "Microsoft.EntityFrameworkCore.SqlServer": "1.0.0",
 "Microsoft.EntityFrameworkCore.Tools": "1.0.0-preview2-final"

```

Looking under References, they appear to be successfully loaded. I then added this under tools in project.json:

```
"Microsoft.EntityFrameworkCore.Tools": {
  "imports": [ "portable-net451+win8" ],
  "version": "1.0.0-preview2-final"
}

```

After I added that, when I build the solution I get this build error:

```
Could not find a part of the path 'C:\Users\(my user name)\.nuget\packages\.tools\Microsoft.EntityFrameworkCore.Tools'

```

I get the same error if I remove the imports line. What am I doing wrong here?