implemented new constructors for DB

db.go

@@ -12,16 +12,19 @@ type Database struct {
 	closefuncs []func() error
 }
 
-func NewDatabase(host string, port uint16, user, pass, db string) (*Database, error) {
+func NewDatabase(conn *sql.DB) *Database {
+	return &Database{
+		db:         conn,
+		closefuncs: make([]func() error, 0),
+	}
+}
+
+func NewMysqlDatabase(host string, port uint16, user, pass, db string) (*Database, error) {
 	conn, err := sql.Open("mysql", connString(host, port, user, pass, db))
 	if err != nil {
 		return nil, adverr.Wrap("could not connect to database", err)
 	}
-
-	return &Database{
-		db:         conn,
-		closefuncs: make([]func() error, 0),
-	}, nil
+	return NewDatabase(conn), nil
 }
 
 func (db *Database) prepare(query string) (*sql.Stmt, error) {