changing the factory to output a sting

  5) Metasploit::Credential::PasswordHash factories metasploit_credential_password_hash should be valid
     Failure/Error: it { should be_valid }
     ActiveRecord::StatementInvalid:
       PG::UndefinedFunction: ERROR:  operator does not exist: text = bigint
       LINE 1: ..."  WHERE ("metasploit_credential_privates"."data" = 13018166...
                                                                    ^
       HINT:  No operator matches the given name and argument type(s). You might need to add explicit type casts.
       : SELECT  1 AS one FROM "metasploit_credential_privates"  WHERE ("metasploit_credential_privates"."data" = 1301816673641498265 AND "metasploit_credential_privates"."type" = 'Metasploit::Credential::Password') LIMIT 1
     # ./spec/models/metasploit/credential/password_hash_spec.rb:14:in `block (4 levels) in <top (required)>'