Truncate Test DB for when working with `before(:all)`

db.rake

# /lib/tasks/db.rake
namespace :db do
  desc "Truncate all table unless running production"
  task :truncate => :environment do
    abort("The Rails environment is running in production mode!") if Rails.env.production?

    ActiveRecord::Base.logger = Logger.new(STDOUT)
    connection = ActiveRecord::Base.connection
    connection.execute("SET FOREIGN_KEY_CHECKS=0;")
    tables = connection.execute("SHOW TABLES").map{|r| r[0]}
    tables.delete "schema_migrations"
    tables.each {|table| connection.execute("TRUNCATE #{table}")}
    connection.execute("SET FOREIGN_KEY_CHECKS=1;")
  end
end