Implemented internal/server/user.Run(). Will be tested with E2E.

internal/server/user/server.go

@@ -1,6 +1,7 @@
 package user
 
 import (
+	"log"
 	"net/http"
 
 	"github.com/BBVA/kapow/internal/server/user/mux"
@@ -10,5 +11,12 @@ var Server = http.Server{
 	Handler: mux.New(),
 }
 
-func Run() {
+func Run(bindAddr string) {
+	Server = http.Server{
+		Addr:    bindAddr,
+		Handler: mux.New(),
+	}
+	if err := Server.ListenAndServe(); err != http.ErrServerClosed {
+		log.Fatalf("UserServer failed: %s", err)
+	}
 }