refactor: consolidate debug flag and update gitignore

- Rename debugMode to isDebug for consistency across codebase
- Move debug flag check in ValidateTimeStamp to match other validations
- Add database.db to gitignore and remove unused config file
- Update README.md to clarify user registration rules

postLog/postLog.go

@@ -8,7 +8,7 @@ import (
 
 var (
 	loggerMutex sync.Mutex
-	debugMode   bool
+	isDebug     bool
 )
 
 const (
@@ -35,7 +35,7 @@ func getSystemTime() string {
 func SetDebugMode(debug bool) {
 	loggerMutex.Lock()
 	defer loggerMutex.Unlock()
-	debugMode = debug
+	isDebug = debug
 }
 
 func PostLog(message string, level int) {
@@ -51,7 +51,7 @@ func PostLog(message string, level int) {
 	defer loggerMutex.Unlock()
 
 	// Skip DEBUG when debug is off
-	if idx == DEBUG && !debugMode {
+	if idx == DEBUG && !isDebug {
 		return
 	}