Create SET cache endpoint

Cache SET endpoint implementation

Closes #3 (closed) FYI: @tziai @valerii.kalashnikov

design/design.go

@@ -41,10 +41,10 @@ var _ = Service("cache", func() {
 	Description("Cache service allows storing and retrieving data from distributed cache.")
 
 	Method("Get", func() {
-		Description("Get value from the cache. The result is a sequence of bytes which the client must decode.")
+		Description("Get JSON value from the cache.")
 
 		Payload(CacheGetRequest)
-		Result(Bytes)
+		Result(Any)
 
 		HTTP(func() {
 			GET("/v1/cache")