add initial project structure with configuration, models, and API key authentication

internal/models/user.go

@@ -0,0 +1,21 @@
+package models
+
+import "time"
+
+type UserRole string
+
+const (
+	UserRoleAdmin UserRole = "admin"
+	UserRoleUser  UserRole = "user"
+)
+
+type User struct {
+	ID           int64     `db:"id"            json:"id"`
+	Username     string    `db:"username"      json:"username"`
+	Email        string    `db:"email"         json:"email"`
+	PasswordHash string    `db:"password_hash" json:"-"`
+	Role         UserRole  `db:"role"          json:"role"`
+	Enabled      bool      `db:"enabled"       json:"enabled"`
+	CreatedAt    time.Time `db:"created_at"    json:"created_at"`
+	UpdatedAt    time.Time `db:"updated_at"    json:"updated_at"`
+}