transportType property Null safety

1. now8
2. domain
3. Route
4. transportType property

Route class

1. Constructors
2. Route
3. fromJson
4. Properties
5. code
6. color
7. hashCode
8. id
9. name
10. runtimeType
11. transportType
12. Methods
13. noSuchMethod
14. toString
15. Operators
16. operator ==