Simple rake example for generating the configs a new developer will need to start up their environment.

dev.rake

DATABASE_YAML = <<-YML
defaults: &defaults
  adapter: mysql2
  username: root
  password:
  host: localhost
  port: 3306

development:
  <<: *defaults
  database: foo_development

test:
  <<: *defaults
  database: foo_test
YML

MONGOID_YAML = <<-YML
development:
  host: localhost
  database: foo_development

test:
  host: localhost
  database: foo_test
YML

namespace :dev do
  namespace :config do
    def write_config(path, content)
      File.open(Rails.root.join('config', path), 'w') do |f|
        f.write content
      end
    end

    desc "Write a developer/testing database.yml"
    task :database => :environment do
      write_config('database.yml', DATABASE_YAML)
    end

    desc "Write a developer/testing mongoid.yml"
    task :mongoid => :environment do
      write_config('mongoid.yml', MONGOID_YAML)
    end
  end

  desc "Write config files for a developer environment."
  task :config => [:"config:database", :"config:mongoid"]
end