steps.rb

# assume the field to search on is "name"
Given /^the ([^\s]+) "([^"]+)" belongs to(?: the) ([^\s]+) "([^"]+)"$/ do |model, value, parent_model, parent_value|
  Given "the #{model} with the name \"#{value}\" belongs to the #{parent_model} with the name \"#{parent_value}\""
end

Given /^the ([^\s]+) with the ([^\s]+) "([^"]+)" belongs to(?: the) ([^\s]+) with the ([^\s]+) "([^"]+)"$/ do |model, field, value, parent_model, parent_field, parent_value|
  # get the id for the first thing
  # get the id for the second thing
  model_id = get_id(model, field, value)
  parent_id = get_id(parent_model, parent_field, parent_value)
  Given "the following #{parent_model} #{model} joins exist:", table(%{
    | #{parent_model}_id | #{model}_id |
    | #{parent_id} | #{model_id} |
  })
end