Run Redis on port 6379

I would rather use a socket to avoid port conflicts, but the GitLab
Rails app ignores the config/resque.yml file when running in the
development or test environment.

redis/redis.conf.example

-port 0
+port 6379
 unixsocket /home/git/redis/redis.socket

redis/resque.yml.example

-development: unix:/home/git/redis/redis.socket
-test: unix:/home/git/redis/redis.socket
+development: redis://localhost:6379
+test: redis://localhost:6379