efcore: Unable to find provider assembly with name Microsoft.EntityFrameworkCore.SqlServer. Ensure the specified name is correct and is referenced by the project.

Steps to reproduce

1. Create a class Library-.Net core
2. Add Following Dependencies:

    "Microsoft.EntityFrameworkCore.Tools": "1.1.0-preview4-final",
    "Microsoft.EntityFrameworkCore.SqlServer": "1.1.0",
    "Microsoft.EntityFrameworkCore.SqlServer.Design": "1.1.0",
    "Microsoft.EntityFrameworkCore.Design": "1.1.0",

The issue

When performing Scaffold-Dbcontext towards a SqlServerDB like below, Microsoft.EntityFramework.SqlServer dll is not resolved… Scaffold-DbContext “Server={ConnectionString}” Microsoft.EntityFrameworkCore.SqlServer -OutputDir Models -verbose

Exception message:
Stack trace:
Microsoft.EntityFrameworkCore.Design.OperationException: Unable to find provider assembly with name Microsoft.EntityFrameworkCore.SqlServer. Ensure the specified name is correct and is referenced by the project. ---> System.IO.FileNotFoundException: Could not load file or assembly 'Microsoft.EntityFrameworkCore.SqlServer, Culture=neutral, PublicKeyToken=null'. The system cannot find the file specified.
   at System.Reflection.RuntimeAssembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks)
   at System.Reflection.RuntimeAssembly.InternalLoadAssemblyName(AssemblyName assemblyRef, Evidence assemblySecurity, RuntimeAssembly reqAssembly, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks)
   at System.Reflection.Assembly.Load(AssemblyName assemblyRef)
   at Microsoft.EntityFrameworkCore.Design.Internal.DesignTimeServicesBuilder.GetProviderDesignTimeServices(String provider, Boolean throwOnError)
   --- End of inner exception stack trace ---
   at Microsoft.EntityFrameworkCore.Design.Internal.DesignTimeServicesBuilder.GetProviderDesignTimeServices(String provider, Boolean throwOnError)
   at Microsoft.EntityFrameworkCore.Design.Internal.DesignTimeServicesBuilder.Build(String provider)
   at Microsoft.EntityFrameworkCore.Design.Internal.DatabaseOperations.ScaffoldContextAsync(String provider, String connectionString, String outputDir, String dbContextClassName, IEnumerable`1 schemas, IEnumerable`1 tables, Boolean useDataAnnotations, Boolean overwriteFiles, CancellationToken cancellationToken)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.<ScaffoldContextImpl>d__22.MoveNext()
   at System.Collections.Generic.EnumerableHelpers.ToArray[T](IEnumerable`1 source, Int32& length)
   at System.Collections.Generic.EnumerableHelpers.ToArray[T](IEnumerable`1 source)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.<>c__DisplayClass4_0`1.<Execute>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)
Unable to find provider assembly with name Microsoft.EntityFrameworkCore.SqlServer. Ensure the specified name is correct and is referenced by the project.

Further technical details

EF Core version: (found in project.json or packages.config) Operating system: Visual Studio version: (e.g. VS 2013 or n/a)

Project.json:

{
  "version": "1.0.0-*",

  "dependencies": {
    "Microsoft.EntityFrameworkCore.Tools": "1.1.0-preview4-final",
    "Microsoft.EntityFrameworkCore.SqlServer": "1.1.0",
    "Microsoft.EntityFrameworkCore.SqlServer.Design": "1.1.0",
    "Microsoft.EntityFrameworkCore.Design": "1.1.0",
    "NETStandard.Library": "1.6.1"
  },

  "frameworks": {
    "netcoreapp1.0": {
    },
    "netstandard1.6": {
      "imports": "dnxcore50"
    }
  },

  "tools": {
    "Microsoft.EntityFrameworkCore.Tools.DotNet": "1.0.0-preview3-final"
  },

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

}