feat: implement database connection and configuration management

- Add database configuration with environment variable support
- Support both PostgreSQL and SQLite database drivers
- Implement connection pooling and timeout configuration
- Add automatic database migration system
- Include connection health checks and error handling
- Configure SSL mode and connection parameters
- Add utility functions for environment variable management

config/database.go

@@ -0,0 +1,26 @@
+package config
+
+import "git.secnex.io/secnex/certman/utils"
+
+// Config holds database configuration
+type Config struct {
+	Host     string
+	Port     string
+	User     string
+	Password string
+	DBName   string
+	SSLMode  string
+	Driver   string // "postgres" or "sqlite"
+}
+
+func GetConfig() *Config {
+	return &Config{
+		Host:     utils.GetEnv("DB_HOST", "localhost"),
+		Port:     utils.GetEnv("DB_PORT", "5432"),
+		User:     utils.GetEnv("DB_USER", "postgres"),
+		Password: utils.GetEnv("DB_PASSWORD", "password"),
+		DBName:   utils.GetEnv("DB_NAME", "certman"),
+		SSLMode:  utils.GetEnv("DB_SSLMODE", "disable"),
+		Driver:   utils.GetEnv("DB_DRIVER", "postgres"),
+	}
+}

database/connection.go

@@ -0,0 +1,103 @@
+package database
+
+import (
+	"fmt"
+	"log"
+	"time"
+
+	"git.secnex.io/secnex/certman/config"
+	"git.secnex.io/secnex/certman/models"
+	"gorm.io/driver/postgres"
+	"gorm.io/driver/sqlite"
+	"gorm.io/gorm"
+	"gorm.io/gorm/logger"
+)
+
+// DB is the global database instance
+var DB *gorm.DB
+
+// Connect establishes database connection and runs migrations
+func Connect() error {
+	config := config.GetConfig()
+
+	var err error
+	var dsn string
+
+	switch config.Driver {
+	case "postgres":
+		dsn = fmt.Sprintf("host=%s port=%s user=%s password=%s dbname=%s sslmode=%s",
+			config.Host, config.Port, config.User, config.Password, config.DBName, config.SSLMode)
+		DB, err = gorm.Open(postgres.Open(dsn), &gorm.Config{
+			Logger: logger.Default.LogMode(logger.Info),
+		})
+	case "sqlite":
+		dsn = config.DBName + ".db"
+		DB, err = gorm.Open(sqlite.Open(dsn), &gorm.Config{
+			Logger: logger.Default.LogMode(logger.Info),
+		})
+	default:
+		return fmt.Errorf("unsupported database driver: %s", config.Driver)
+	}
+
+	if err != nil {
+		return fmt.Errorf("failed to connect to database: %w", err)
+	}
+
+	// Configure connection pool
+	sqlDB, err := DB.DB()
+	if err != nil {
+		return fmt.Errorf("failed to get underlying sql.DB: %w", err)
+	}
+
+	// Set connection pool settings
+	sqlDB.SetMaxIdleConns(10)
+	sqlDB.SetMaxOpenConns(100)
+	sqlDB.SetConnMaxLifetime(time.Hour)
+
+	log.Printf("Successfully connected to %s database", config.Driver)
+
+	// Run migrations
+	if err := Migrate(); err != nil {
+		return fmt.Errorf("failed to run migrations: %w", err)
+	}
+
+	return nil
+}
+
+// Migrate runs database migrations for all models
+func Migrate() error {
+	log.Println("🚀 Running database migrations...")
+
+	err := DB.AutoMigrate(
+		&models.CertificateAuthority{},
+		&models.Certificate{},
+		&models.CertificateRequest{},
+		&models.CertificateRevocationList{},
+		&models.Organization{},
+		&models.User{},
+	)
+
+	if err != nil {
+		return fmt.Errorf("migration failed: %w", err)
+	}
+
+	log.Println("✅ Database migrations completed successfully")
+	return nil
+}
+
+// Close closes the database connection
+func Close() error {
+	if DB != nil {
+		sqlDB, err := DB.DB()
+		if err != nil {
+			return fmt.Errorf("failed to get underlying sql.DB: %w", err)
+		}
+		return sqlDB.Close()
+	}
+	return nil
+}
+
+// GetDB returns the database instance
+func GetDB() *gorm.DB {
+	return DB
+}