Added chat microservice, removed air

chat-service/services/chat.go

@@ -0,0 +1,11 @@
+package service
+
+import (
+	"net/http"
+	"twitch-clone/chat-service/models"
+)
+
+type ChatService interface {
+	Subscribe(http.ResponseWriter, *http.Request) error
+	Publish(string, *models.ChatMessage) error
+}