migration error in cassandra

i am using cassandra in my rails project, I am new to this cassandra and i am trying to use Bigrecord api to connect with cassandra and i reffered below link

http://openplaces.github.com/bigrecord/file.getting_started.html

while migrating the bigrecord i am using this command rake bigrecord:migrate but it is showing some error like this

rake aborted!

This database does not yet support migrations

can any one help me to solve this problem

thanks in advanc开发者_高级运维e

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Bigrecord currently only supports HBase. Cassandra is not yet supported.