Changed which messages are forwardable

Challenges should be forwardable. Group creation  should be done by
users on the local server as otherwise groups will get squatted
incredibly easily and quickly

src/client.rs

@@ -1,6 +1,6 @@
 use uuid::Uuid;
 use crate::message::{MessageId,TaggedMessage,VerificationError,Relevance};
-use crate::state::{self,StateType,StateValue,StatePath,StatePermission,StatePermissionKey};
+use crate::state::{self,StateValue,StatePath,StatePermission,StatePermissionKey};
 use crate::{RoomId,Group,Role,User,GroupPower,ServerAddr};
 use serde::{Deserialize, Serialize};
 use time::OffsetDateTime;
@@ -250,11 +250,17 @@ impl ClientMessage<> {
               username: _,
               password: _,
           }
+          // Groups can only be created locally. However, you can still
+          // grant admin permissions to users on other servers
+          | GroupCreate {
+              users: _,
+              group: _,
+          } => false,
           // In the future challenges might be forwardable but right now they are
           // only used for signups and auth is local.
-          | ChallengeAnswer {
-              response: _
-          } => false,
+          //| ChallengeAnswer {
+          //    response: _
+          //} => false,
 
           _  => true
         }
@@ -322,6 +328,7 @@ pub enum ServerError {
     RemoveLastOwner,
     MessageNotForwardable,
     UserAlreadyExists,
+    MissingPermission,
     Generic