Do not leave group when following is active

back/src/Model/GameRoom.ts

@@ -139,6 +139,7 @@ export class GameRoom {
             joinRoomMessage.getIpaddress(),
             position,
             false,
+            [],
             this.positionNotifier,
             socket,
             joinRoomMessage.getTagList(),
@@ -231,7 +232,7 @@ export class GameRoom {
             // If the user is part of a group:
             //  should he leave the group?
             const distance = GameRoom.computeDistanceBetweenPositions(user.getPosition(), user.group.getPosition());
-            if (distance > this.groupRadius) {
+            if (user.following.length === 0 && distance > this.groupRadius) {
                 this.leaveGroup(user);
             }
         }

back/src/Model/User.ts

@@ -25,6 +25,7 @@ export class User implements Movable {
         public readonly IPAddress: string,
         private position: PointInterface,
         public silent: boolean,
+        public following: string[],
         private positionNotifier: PositionNotifier,
         public readonly socket: UserSocket,
         public readonly tags: string[],
@@ -48,6 +49,21 @@ export class User implements Movable {
         this.positionNotifier.updatePosition(this, position, oldPosition);
     }
 
+    public addFollower(name: string): void {
+        if (this.following.includes(name)) {
+            return;
+        }
+        this.following.push(name);
+    }
+
+    public delFollower(name: string): void {
+        const idx = this.following.indexOf(name);
+        if (idx === -1) {
+            return;
+        }
+        this.following.splice(idx, 1);
+    }
+
     private batchedMessages: BatchMessage = new BatchMessage();
     private batchTimeout: NodeJS.Timeout | null = null;