Applied validation

src/main/java/net/gepafin/tendermanagement/util/FieldValidator.java

@@ -62,4 +62,7 @@ public class FieldValidator {
 		errors.add(errorMessage);
 		return this;
 	}
+	public static boolean isNullOrZero(Long value) {
+		return value == null || value == 0L;
+	}
 }