Example of a custom rake file in a ruby app with out rails.

Rakefile.rb

require 'active_record'
require 'yaml'
require 'logger'
require 'database_cleaner'
require_relative 'models/market'

CONFIG = YAML::load(File.open('config/database.yml'))

task :default => :migrate
namespace :db do
  desc "Migrate the database through scripts in db/migrate. Target specific version with VERSION=x"
  task :migrate => :environment do
    ActiveRecord::Migrator.migrate('db/migrate', ENV["VERSION"] ? ENV["VERSION"].to_i : nil )
  end

  task :drop => :environment do
    puts "----- Drop DB -----"
    ActiveRecord::Base.connection.drop_database CONFIG["database"]
  end

  task :create do
    puts "----- Create DB -----"
    config = YAML::load(File.open('config/database.yml'))
    config['database'] = 'mysql'
    ActiveRecord::Base.establish_connection config
    ActiveRecord::Base.connection.create_database CONFIG["database"]

    ActiveRecord::Base.establish_connection YAML::load(File.open('config/database.yml'))
  end

  task :reset => :environment do
    puts "----- Reset DB -----"
    Rake::Task["db:drop"].invoke
    Rake::Task["db:create"].invoke
    Rake::Task["db:migrate"].invoke
    Rake::Task["db:seed"].invoke
  end
  
  desc "Truncate all existing data"
  task :truncate, [:arg1] => :environment do |t, args|
    if args[:arg1] =~ /all/i
      DatabaseCleaner.clean_with :truncation
    else
      DatabaseCleaner.clean_with :truncation, { only: [args[:arg1]] }
    end
  end

  task :seed => :environment do
    markets = Market.all
    if markets.length == 0
      names = %w[Alabama Illinois MAPA Tennessee Texas]
      names.each do |name|
        puts "\tSeeding Markets with market_name: #{name}"
        Market.create market_name: name
      end
      puts "Finished seeding markets"
      puts
    end
  end
end

task :environment do
  ActiveRecord::Base.establish_connection YAML::load(File.open('config/database.yml'))
  ActiveRecord::Base.logger = Logger.new(File.open('log/database.log', 'a'))
end

# Happy Rubying =)