add custom callbacks

src/pages/api/auth/[...nextauth].ts

@@ -27,6 +27,28 @@ export const authOptions = {
       },
     },
   ],
+  callbacks: {
+    async jwt({ token, user }) {
+      // Initial sign in
+      if (user) {
+        token.id = user.id;
+        token.username = user.username;
+        token.is_volunteer = user.is_volunteer;
+        token.is_member = user.is_member;
+        token.last_membership = user.last_membership;
+        token.groups = user.groups;
+      }
+      return token;
+    },
+    async session({ session, token, user }) {
+      session.user.username = token.username;
+      session.user.is_volunteer = token.is_volunteer;
+      session.user.is_member = token.is_member;
+      session.user.last_membership = token.last_membership;
+      session.user.groups = token.groups;
+      return session;
+    },
+  },
 };
 
 export default NextAuth(authOptions);