title: Unable to resolve dependency with configuration file settings
body: <p>I am kind of new to the dependency injection resolver techniques topic. May I know how we can resolve dependency through configuration file section(s). Below are my classes and interface along with the config file.</p>
  
  <p>I am sure that missing some portion of code/setting. Can you please help me with this.</p>
  
  <pre class="lang-cs prettyprint-override"><code>public interface IUserAuthentication
  {
      string Authenticate(string username, string password);
      string GetUserRole(string username);
  }
  
  public class CloudAppAuthetication : IUserAuthentication
  {
      public string Authenticate(string username, string password)
      {
          //Jwt token based authentication logic should be there
          return "This Authenticate method executed from cloud class";
      }
  
      public string GetUserRole(string username)
      {
          //New logic to user management api call
          return "This GetUserRole method executed from cloud class";
      }
  }
  
  public class StandaloneAppAuthetication : IUserAuthentication
  {
      public string Authenticate(string username, string password)
      {
          //current logic should be here
          return "This Authenticate method executed from standalone class";
      }
  
      public string GetUserRole(string username)
      {
          //current logic should be here
          return "This GetUserRole method executed from standalone class";
      }
  }
  </code></pre>
  
  <p>Console application calling of interface method:</p>
  
  <pre class="lang-cs prettyprint-override"><code>class Program
  {
      static void Main(string[] args)
      {
          IUnityContainer container = new UnityContainer();
          container.LoadConfiguration("TestContainer");
          IUserAuthentication _userAuthentication = null;
          string validatedUser = _userAuthentication.Authenticate(
              "testuser@user.com", "testpassword");
          string validatedUserRole =
              _userAuthentication.GetUserRole("testuser@user.com");
      }
  }
  </code></pre>
  
  <p>My App.config file of console application is:</p>
  
  <pre class="lang-xml prettyprint-override"><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
    &lt;configuration&gt;
      &lt;configSections&gt;
         &lt;section name="unity"
    type="Microsoft.Practices.Unity.Configuration.UnityConfigurationSection,
  Microsoft.Practices.Unity.Configuration" /&gt;
      &lt;/configSections&gt;
      &lt;unity xmlns = "http://schemas.microsoft.com/practices/2010/unity" &gt;
        &lt; container name="TestContainer"&gt;
          &lt;register
    type="UnityConfiguration_Testing.IUserAuthentication,UnityConfiguration_Testing"
    mapTo="UnityConfiguration_Testing.StandaloneAppAuthetication,UnityConfiguration_Testing"
          /&gt;
        &lt;/container&gt;
      &lt;/unity&gt;
    &lt;startup&gt;
      &lt;supportedRuntime version = "v4.0" sku=".NETFramework,Version=v4.5" /&gt;
    &lt;/startup&gt;
  &lt;/configuration&gt;
  </code></pre>
  
  <p>I am getting object reference not set to an instance of object error. Expecting that <code>StandaloneAppAuthetication</code> class method will get executed as per my configuration.</p>