Fix loading errors in non-rails apps and rails apps with db-charmer used as a gem, not a plugin
user
```ruby
module DbCharmer
  module Sharding
    module Method
      autoload :Range, 'db_charmer/sharding/method/range'
      autoload :HashMap, 'db_charmer/sharding/method/hash_map'
      autoload :DbBlockMap, 'db_charmer/sharding/method/db_block_map'
      autoload :DbBlockGroupMap, 'db_charmer/sharding/method/db_block_group_map'
    end
  end
end```
assistant