undefined method `namespace' for main:Object (NoMethodError) - active record / rakefile

Question

I'm attempting to run a basic Sinatra app. When I get to the 'rackup' step I get an error:

/.rvm/gems/ruby-2.2.1/gems/activerecord-4.2.1/lib/active_record/railties/databases.rake:3:in `<top (required)>': undefined method `namespace' for main:Object (NoMethodError)

It seems to be a scope issue in the Rake gem. I've had no luck findding an answer and I'm not quite sure what needs to be fixed. I did update all my gems in hopes that would help to no avail. Here is my code that might be contributing....

    rakefile.rb
       require "./frank"
       require "sinatra/activerecord/rake"

    config.ru
        require_relative 'frank'
        map('/welcomes') { run WelcomesController }

    frank.rb
        require 'sinatra/base'
        require 'active_record'
        require 'bcrypt'

        Dir.glob('./{controllers,models}/*rb').each { |file| require file }

        ENV['SINATRA_ENV'] ||= 'development'

        ActiveRecord::Base.establish_connection(
            :adapter => 'sqlite3',
            :database => "db/#{ENV['SINATRA_ENV']}.sqlite"
        )

    spec_helper.rb
        ENV['SINATRA_ENV'] = 'test'
        require_relative '../frank'
        require 'capybara'
        require 'database_cleaner'
        Capybara.app = Rack::Builder.parse_file(File.expand_path('../../config.ru',__FILE__)).first
    RSpec.configure do |config|
        config.include Capybara::DSL
        config.before(:suite) do
            DatabaseCleaner.clean_with(:truncation)
    end
    config.before(:each) do
          DatabaseCleaner.strategy = :transaction
    end
    config.before(:each) do
          DatabaseCleaner.start
    end
    config.after(:each) do
        DatabaseCleaner.clean
    end
end

Many thanks :)

This is below the primary error:

    from /Users/stephaniedean/.rvm/gems/ruby-2.2.1/gems/sinatra-activerecord-2.0.6/lib/sinatra/activerecord/rake.rb:1:in `load'
    from /Users/stephaniedean/.rvm/gems/ruby-2.2.1/gems/sinatra-activerecord-2.0.6/lib/sinatra/activerecord/rake.rb:1:in `<top (required)>'

So, it looks like sinatra-activerecord not just activerecord. I did try activerecord 3.2.17 that didn't work. Thanks for the suggestions.

Answer 1

this took up hours of my time before I found the solution:

http://aaronlerch.github.io/blog/sinatra-bundler-and-the-global-namespace/ https://github.com/sinatra/sinatra-contrib/issues/111

Gemfile

gem "sinatra", require: 'sinatra/base'
gem 'sinatra-activerecord', require: false
gem 'sinatra-contrib', require: false

Environment.rb

require 'bundler/setup'
require 'rake'
require 'sinatra'
require 'sinatra/reloader'
require 'sinatra/activerecord'
require 'sinatra/activerecord/rake'

make sure to

require 'rake'

before

require 'sinatra/activerecord/rake'