addTag method
- String tag
//////////// //////////// Adds a tag to the route
Implementation
// II.F - Tag Methods
///////////////
/// Adds a tag to the route
RaliRoute addTag(String tag) {
if (tags.contains(tag)) return this;
final newTags = List<String>.from(tags);
newTags.add(tag);
return copyWith(tags: newTags);
}