Support custom SQLite database file name

Ref T529

.gitignore

@@ -4,4 +4,4 @@
 
 build
 config.ini
-writefreely.db
+*.db

app.go

@@ -486,7 +486,11 @@ func connectToDatabase(app *app) {
 		db, err = sql.Open(app.cfg.Database.Type, fmt.Sprintf("%s:%s@tcp(%s:%d)/%s?charset=utf8mb4&parseTime=true&loc=%s", app.cfg.Database.User, app.cfg.Database.Password, app.cfg.Database.Host, app.cfg.Database.Port, app.cfg.Database.Database, url.QueryEscape(time.Local.String())))
 		db.SetMaxOpenConns(50)
 	} else if app.cfg.Database.Type == "sqlite3" {
-		db, err = sql.Open("sqlite3", "./writefreely.db?parseTime=true&cached=shared")
+		if app.cfg.Database.FileName == "" {
+			log.Error("SQLite database filename value in config.ini is empty.")
+			os.Exit(1)
+		}
+		db, err = sql.Open("sqlite3", app.cfg.Database.FileName+"?parseTime=true&cached=shared")
 		db.SetMaxOpenConns(1)
 	} else {
 		log.Error("Invalid database type '%s'. Only 'mysql' and 'sqlite3' are supported right now.", app.cfg.Database.Type)

config/config.go

@@ -22,6 +22,7 @@ type (
 
 	DatabaseCfg struct {
 		Type     string `ini:"type"`
+		FileName string `ini:"filename"`
 		User     string `ini:"username"`
 		Password string `ini:"password"`
 		Database string `ini:"database"`