title: 'IApplicationBuilder' does not contain a definition for 'UseSession'
body: <p>I am building an app using ASP.NET Core 2.0 which was earlier using Core 1.0. After migration everything seems to be working fine but when i try to use Session method <code>app.UseSession()</code> then it throws following error:</p>
  
  <blockquote>
    <p>'IApplicationBuilder' does not contain a definition for 'UseSession' and no extension method 'UseSession' accepting a first argument of type 'IApplicationBuilder' could be found (are you missing a using directive or an assembly reference?)</p>
  </blockquote>
  
  <p>I tried installing <code>ASPNETCore.Session</code> package from NuGet but couldn't.</p>
  
  <p>Can anyone help me finding the root cause of the issue?</p>