Add example Eager Loading function.

EntityFrameworkCore.Console/Program.cs

@@ -15,6 +15,23 @@ context.Database.EnsureCreated();
 // Rather than raise: "System.InvalidOperationException: Sequence contains no elements."
 // var firstCoach = await context.Coaches.FirstOrDefaultAsync();
 
+async Task EagerLoadingExample()
+{
+  var leagues = await context.Leagues
+    .Include(l => l.Teams)
+    .ThenInclude(t => t.Coach)
+    .ToListAsync();
+
+  foreach (var league in leagues)
+  {
+    Console.WriteLine($"League - {league.Name}");
+    foreach (var team in league.Teams)
+    {
+      Console.WriteLine($"* {team.Name} - {team.Coach.Name}");
+    }
+  }
+}
+
 async Task InsertRelatedData()
 {
   // Insert record with a Foreign Key.