Allow setting fields previously unset, like adding a connection when it was nil in db

storage/graph_test.go

@@ -342,6 +342,34 @@ func TestIntegration(t *testing.T) {
 		}
 	})
 
+	t.Run("graph.Update connections when none previously", func(t *testing.T) {
+		cleanFill()
+		one := randomOne()
+		one.Connections = nil
+		err := graph.Insert(ctx, "col", one)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		err = graph.Update(ctx, "col", one.Query(), operator.Set{Key: entity.Connections + ".newfriend", Value: randomOne()})
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		ones, err = graph.ListCaseInsensitive(ctx, "col", one.Name)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if len(ones) != 1 {
+			t.Fatal(ones)
+		}
+		if len(ones[0].Connections) != 1 {
+			t.Fatal(ones[0].Connections)
+		}
+		if _, ok := ones[0].Connections["newfriend"]; !ok {
+			t.Fatal(ones[0].Connections)
+		}
+	})
 }
 
 func randomOne() entity.One {