Add sequel scope all with default scope bench

[bmarkons]

Sequel default scope benchmark 📈

[noahgibbs]

In general, this looks good. I don't think I see the "admin" boolean field in the schema for the pg and ActiveRecord flavors of this benchmark. Is that intentional?

[bmarkons]

Actually admin field exists in schema for ActiveRecord default scope benchmark. Take a look at line #12. As opposed to scope all benchmarks of all flavors where admin field isn't added.

Do you suggest that scope all benchmarks and default scope benchmarks should have same schemas?

[noahgibbs]

Ah, I probably read the wrong file, then. Sorry, if all the scope all benchmarks have the same schema then I was wrong. Carry on :-)

[bmarkons]

Can I merge this one? This benchmark is comparable to https://github.com/ruby-bench/ruby-bench-suite/blob/master/rails/benchmarks/bm_activerecord_scope_all_with_default_scope.rb