Update 2. Build out BackEnd and Refactor.md

Author: davidfowl

docs/2. Build out BackEnd and Refactor.md

@@ -233,24 +233,24 @@ We're also going to take this opportunity to rename the `Models` directory in th
    ```
  1. Add an `SessionAttendee.cs` class with the following code:
    ```csharp
-	using System;
-	using System.Collections.Generic;
-	using System.Linq;
-	using System.Threading.Tasks;
+    using System;
+    using System.Collections.Generic;
+    using System.Linq;
+    using System.Threading.Tasks;
 
-	namespace BackEnd.Data
-	{
-		public class SessionAttendee
-		{
-			public int SessionID { get; set; }
+    namespace BackEnd.Data
+    {
+        public class SessionAttendee
+        {
+            public int SessionID { get; set; }
 
-			public Session Session { get; set; }
+            public Session Session { get; set; }
 
-			public int AttendeeID { get; set; }
+            public int AttendeeID { get; set; }
 
-			public Attendee Attendee { get; set; }
-		}
-	}
+            public Attendee Attendee { get; set; }
+       }
+   }
    ```
 1. Add an `Attendee.cs` class with the following code:
    ```csharp