Do not load RubyGems ourselves.

When gem is installed RubyGems creates wrappers that inject RubyGems into the
environment. So requiring rubygem in bin/sequenceserver is not warranted.

During development, it's recommended to use `bundle exec bin/sequenceserver` or
`rackup -I lib` where `bundle exec` and `rackup` will ensure RubyGems is loaded.

IIRC, `mod_passenger` loads RubyGems and activates Gemfile by default.

In short, we don't need to `require 'rubygems'` anywhere in our code base, If a
user's deploy setup is not behaving as expected, options such as setting
environment variables (like RUBYOPT) or a deploy script that loads RubyGems
should be explored first.

Signed-off-by: Anurag Priyam <anurag08priyam@gmail.com>