add db filepath

internal/config/config.go

@@ -2,10 +2,18 @@ package config
 
 import "os"
 
-func GetStoryFilePath() string {
+func GetStoryFilepath() string {
 	storyFilename := os.Getenv("STORY_FILENAME")
 	if storyFilename != "" {
 		return storyFilename
 	}
 	return "./data/story/story.json"
 }
+
+func GetDBFilepath() string {
+	storyFilename := os.Getenv("DB_FILENAME")
+	if storyFilename != "" {
+		return storyFilename
+	}
+	return "data/db/store.db"
+}