Show active route in sidebar of /builds.

Screenshots:

Home:
![home](https://www.monosnap.com/image/CgzYcbetNmPUmPVScz6ph9Tka.png)

Tagged:
![tagged](https://www.monosnap.com/image/eNmK3G5HTf5lqmAIa4JcgmXsL.png)

Release:
![release](https://www.monosnap.com/image/OIGAiDAkSADVQ7YfRg31U1dyg.png)

Beta:
![beta](https://www.monosnap.com/image/kGvWLXPGEFpE5lHdBnzeVO4fq.png)

Canary:
![canary](https://www.monosnap.com/image/Qpbgw4rjjvF5glv86uT8jz0Qg.png)