Leaving it out of the `attr_accessible`, you can still do things like:
```ruby
user.streak += 1
user.save!
```
But you wouldn't be able to do something like this:
```ruby
user.update_attributes(streak: 2)
```
This is because it hasn't been added to the whitelist (via `attr_accessible`) of attributes that can be mass-assigned. This prevents users from doing malicious things like submitting curl requests with streak in the params or tinkering with the users form so they can set their own streak.