Convenience methods for test preparation

Creates a `Cequel::SpecSupport::Preparation` class that can be used to ensure a clean and fully synced test db by adding the following to the bottom of one's `spec_helper.rb` (below the `RSpec.configure` block).

```ruby
# one time setup
Cequel::SpecSupport::Preparation.setup_database(Rails.root + "app/models")
```