update database driver to modernc.org/sqlite and add Dockerfile with multi-stage build

sql/client.go

@@ -4,7 +4,8 @@ import (
 	"context"
 	"database/sql"
 	sqlc "git.siteworxpro.com/gun-manager/sql/db"
-	_ "github.com/mattn/go-sqlite3"
+
+	_ "modernc.org/sqlite"
 )
 
 type Db struct {
@@ -20,7 +21,7 @@ func NewDb(file string) (*Db, error) {
 		return &dbConnection, nil
 	}
 
-	db, err := sql.Open("sqlite3", file)
+	db, err := sql.Open("sqlite", file)
 	if err != nil {
 		return nil, err
 	}