```ruby
module ActiveSupport::Cache
  class Store
    def expire(options = {})
        tags = options[:tags]
        cache_version = read("$cache_version").to_i
  
        write("$cache_version", cache_version + 1)
    end
    
    def expire_tag_version
      # $tag_version is bumped when the type of a tag is changed in Tags, if
      # a new tag is created, or if a tag's post_count becomes nonzero.
      incr("$tag_version")
    end
  
    def incr(key)
        val = read(key)
        write(key, val.to_i + 1)
    end
  end
end
```

Use time for cache_version instead of random (incrementing) integer.
user
```ruby
module ActiveSupport::Cache
  class Store
    def expire(options = {})
      write('$cache_version', Time.now.to_i)
    end

    def expire_tag_version
      # $tag_version is bumped when the type of a tag is changed in Tags, if
      # a new tag is created, or if a tag's post_count becomes nonzero.
      incr("$tag_version")
    end
  
    def incr(key)
        val = read(key)
        write(key, val.to_i + 1)
    end
  end
end
```
assistant