rm redundant bit from dbcontext

Author: maurei

test/OpenApiTests/OpenApiDbContext.cs

@@ -16,11 +16,5 @@ public OpenApiDbContext(DbContextOptions<OpenApiDbContext> options)
             : base(options)
         {
         }
-
-        protected override void OnModelCreating(ModelBuilder builder)
-        {
-            builder.Entity<Airplane>()
-                .HasMany(airplane => airplane.Flights);
-        }
     }
 }