Refactor for ruby 2.0+ and rails 5.0+

[benlinton]

This project hasn't been maintained for a long time. And I was unable to get the tests running (tried ruby 1.9.3 and 2.3.3). So I generated a new gem using the bundle command, and then ported over the existing code into the newly generated gem.

Change Log:

• Bumped the version from 0.0.2 to 1.0.0 since this is a potential breaking change
• Tests were ported over to RSpec, which is the new bundler-generated default
• Added support for Ruby 2.0, mainly by replacing alias_method_chain with prepend
• Added support for OWNED BY option for sequence CREATE and ALTER PostgreSQL
• Added pry and removed guard as development dependencies
• Removed license copy from individual files, in favor of a global license file. Also, I'm not sure which license we should use, since this code was originally copied from the foreigner gem.

A fix was made for this PR in #8

[benlinton]

Closing this so in order to make a single pull request that has all 1.0.x changes.