Add compatibility with rails 5

[mgrachev]

I get the following error when using this gem with rails 5.0.0.beta1:

/Users/mgrachev/mm/vendor/bundle/gems/marginalia-1.3.0/lib/marginalia.rb:55:in `exec_query_with_marginalia': wrong number of arguments (4 for 1..3) (ArgumentError)
from /Users/mgrachev/mm/vendor/bundle/gems/activerecord-5.0.0.beta1/lib/active_record/connection_adapters/abstract/database_statements.rb:375:in `select_prepared'
from /Users/mgrachev/mm/vendor/bundle/gems/activerecord-5.0.0.beta1/lib/active_record/connection_adapters/abstract/database_statements.rb:39:in `select_all'
from /Users/mgrachev/mm/vendor/bundle/gems/activerecord-5.0.0.beta1/lib/active_record/connection_adapters/abstract/query_cache.rb:70:in `select_all'
from /Users/mgrachev/mm/vendor/bundle/gems/activerecord-5.0.0.beta1/lib/active_record/querying.rb:39:in `find_by_sql'
from /Users/mgrachev/mm/vendor/bundle/gems/activerecord-5.0.0.beta1/lib/active_record/relation.rb:691:in `exec_queries'
from /Users/mgrachev/mm/vendor/bundle/gems/activerecord-5.0.0.beta1/lib/active_record/relation.rb:572:in `load'
from /Users/mgrachev/mm/vendor/bundle/gems/activerecord-5.0.0.beta1/lib/active_record/relation.rb:252:in `to_a'
from /Users/mgrachev/mm/vendor/bundle/gems/activerecord-5.0.0.beta1/lib/active_record/relation/delegation.rb:39:in `map'
from /Users/mgrachev/mm/vendor/bundle/gems/activerecord-5.0.0.beta1/lib/active_record/migration.rb:1002:in `block in get_all_versions'
from /Users/mgrachev/mm/vendor/bundle/gems/activesupport-5.0.0.beta1/lib/active_support/deprecation/reporting.rb:34:in `silence'
from /Users/mgrachev/mm/vendor/bundle/gems/activesupport-5.0.0.beta1/lib/active_support/deprecation/instance_delegator.rb:19:in `silence'
from /Users/mgrachev/mm/vendor/bundle/gems/activerecord-5.0.0.beta1/lib/active_record/migration.rb:1000:in `get_all_versions'
from /Users/mgrachev/mm/vendor/bundle/gems/activerecord-5.0.0.beta1/lib/active_record/migration.rb:1014:in `needs_migration?'
from /Users/mgrachev/mm/vendor/bundle/gems/activerecord-5.0.0.beta1/lib/active_record/migration.rb:548:in `load_schema_if_pending!'
from /Users/mgrachev/mm/vendor/bundle/gems/activerecord-5.0.0.beta1/lib/active_record/migration.rb:563:in `block in maintain_test_schema!'
from /Users/mgrachev/mm/vendor/bundle/gems/activerecord-5.0.0.beta1/lib/active_record/migration.rb:794:in `suppress_messages'
from /Users/mgrachev/mm/vendor/bundle/gems/activerecord-5.0.0.beta1/lib/active_record/migration.rb:568:in `method_missing'
from /Users/mgrachev/mm/vendor/bundle/gems/activerecord-5.0.0.beta1/lib/active_record/migration.rb:563:in `maintain_test_schema!'

This PR adds compatibility with new version rails and fix this error.

[arthurnn]

This will raise an syntax error on 1.9.3 https://travis-ci.org/basecamp/marginalia/jobs/103911750
Maybe, we should use an hash instead?
Thanks for the PR

[mgrachev]

Fixed

[mgrachev]

@arthurnn All right with PR or need something to modify?

[arthurnn]

thanks