FIX: update group user count when bulk adding users

app/models/group.rb

@@ -534,6 +534,16 @@ class Group < ActiveRecord::Base
       if user_attributes.present?
         User.where(id: user_ids).update_all(user_attributes)
       end
+
+      # update group user count
+      Group.exec_sql <<-SQL.squish
+        UPDATE groups g
+        SET user_count =
+          (SELECT COUNT(gu.user_id)
+           FROM group_users gu
+           WHERE gu.group_id = g.id)
+        WHERE g.id = #{self.id};
+      SQL
     end
 
     if self.grant_trust_level.present?

spec/models/group_spec.rb

@@ -619,6 +619,13 @@ describe Group do
 
       expect(group.group_users.map(&:user_id)).to contain_exactly(user.id, admin.id)
     end
+
+    it 'updates group user count' do
+      expect {
+          group.bulk_add([user.id, admin.id])
+          group.reload
+        }.to change { group.user_count }.by(2)
+    end
   end
 
   it "Correctly updates has_messages" do