BSON::Binary::InvalidType "my file content" is not a valid binary type. Please use one of :generic, :function, :old, :uuid_old, :uuid, :md5, :user.):

Question

I am trying to save files into gridfs using carrierwave mongoid in rails. I am unable to do this process due to this error:

BSON::Binary::InvalidType ("my file content" is not a valid binary type. 
Please use one of :generic, :function, :old, :uuid_old, :uuid, :md5, :user.):

Can anyone please help me out of this problem?

Thanks in advance.