add godoc to cache interface

server/cache/interface.go

@@ -2,6 +2,7 @@ package cache
 
 import "time"
 
+// ICache is an interface that defines how the pages server interacts with the cache.
 type ICache interface {
 	Set(key string, value interface{}, ttl time.Duration) error
 	Get(key string) (interface{}, bool)