Initial checkin

common/db/db.go

@@ -0,0 +1,22 @@
+package db
+
+import "fmt"
+
+type User struct {
+	ID int
+}
+
+func LoadUser(id int) (User, error) {
+	if id < 0 {
+		return User{}, fmt.Errorf("invalid negative user id '%d'", id)
+	}
+	if id > 100 {
+		return User{}, fmt.Errorf("invalid user id '%d'", id)
+	}
+
+	return User{ID: id}, nil
+}
+
+func (u User) String() string {
+	return fmt.Sprintf("this user is id: %d", u.ID)
+}