AvroRecord doesn't handle CamelCased models correctly

[karlhe]

Namely, this line is suspect:

$CLIENT.send(self.class.to_s.downcase.pluralize).put(avro_pair.key, avro_pair.value)

As in, the following unexpected behavior will happen:

# For class HashTag
$CLIENT.hash_tags # => error
$CLIENT.hashtags  # => success

Easily fixed by doing the following:

$CLIENT.send(self.class.to_s.underscore.downcase.pluralize).put(avro_pair.key, avro_pair.value)

However, as Gradit is already working around this in GraditClient.scala, changing it at this point would break Gradit so I'll leave it as an open isue.