mongoid/mongoid — Issue #1775: When using (store_in capped:true) cannot delete_all
Author: pmq20
Created: 2012-02-29 09:47:01+00:00
State: open

Example:
```ruby
class TopicCache
include Mongoid::Document
store_in :topic_caches,capped:true,size:100000 # 10000 = 127 records
field :name
field :followers_count
field :hot_rank
index :name
end
```

Cannot
```ruby
TopicCache.delete_all
```

After which though the method suceeded the record is not deleted at all.

Instead, have to do
```ruby
Mongoid.database.collection('topic_caches').drop
```