update graphql schema

@@ -11,28 +11,30 @@ type User {
   rooms: [Room]
   createdAt: String
   messages: [Message]
-  from: Message
-  to: [Message]
+  sender: [User]
+  receiver: [User]
 }
 
 type Room {
   id: ID!
+  name: String!
   participants: [User]
   categories: [Category]
+  messages: [Message]
 }
 
 type Category {
   id: ID!
   name: String
-  rooms: [Room]
+  room: Room
 }
 
 type Message {
   id: ID!
   text: String!
-  from: [User]
-  to: [User]
-  room: Room!
+  sender: User
+  room: Room
+  category: Category
   createdAt: String
   updatedAt: String
 }