Deactivate a Gem - "you have already activated rake 0.9.3.beta.1, but my Gemfile requires rake 0.9.2"

Question

I'm trying to run a migration but I keep getting the error message that is:

rake aborted! Undefined method prerequisite for nil:NilClass.

It seems that somehow I activated a gem called rake 0.9.3.beta.1 - however I have since changed the gem bundle install and run bundle show rake and it shows that rake 0.9.2 is installed. I'm using Git for the first time so I thought that maybe it had something to do with the application still using the beta version of rake - but I've done a push and it shows that the gemfile has been updated.

and when I look down into the gem libraries I can only see the rake 0.9.2 version. Where should I be looking?

I also have a Rails:Railtie deprecated warning - but I'm thinking that this doesn't have anything to do with my migration problems. Its telling me to use config.app_generators in config/application.rb instead of Railtie - but i can't see that in the file.

This is the Config/application.rb file

require File.expand_path('../boot', __FILE__)

# Pick the frameworks you want:
 require "active_record/railtie"
require "action_controller/railtie"
require "action_mailer/railtie"
require "active_resource/railtie"
 require "sprockets/railtie"
Bundler.require *Rails.groups(:assets) if defined?(Bundler)

module CrowdshareApp
  class Application < Rails::Application
  config.encoding = "utf-8"
config.filter_parameters += [:password]
config.assets.enabled = true
  end
end

My Gemfile looks like this:

source 'http://rubygems.org'

gem 'rails', '3.1.0.rc5'
gem 'sqlite3' 
group :assets do
  gem 'sass-rails', "~> 3.1.0.rc"
  gem 'coffee-rails', "~> 3.1.0.rc"
  gem 'uglifier'
end

gem 'jquery-rails'
group :development do
  gem   'rspec-rails', '2.0.0.beta.18'
end

group :test do
  gem 'rspec', '2.0.0.beta.18'
end

and the Gemfile.lock file has the following:

GEM
  remote: http://rubygems.org/
  specs:
    actionmailer (3.1.0.rc5)
      actionpack (= 3.1.0.rc5)
      mail (~> 2.3.0)
    actionpack (3.1.0.rc5)
      activemodel (= 3.1.0.rc5)
      activesupport (= 3.1.0.rc5)
      builder (~> 3.0.0)
      erubis (~> 2.7.0)
      i18n (~> 0.6)
      rack (~> 1.3.1)
      rack-cache (~> 1.0.2)
      rack-mount (~> 0.8.1)
      rack-test (~> 0.6.0)
      sprockets (~> 2.0.0.beta.12)
    activemodel (3.1.0.rc5)
      activesupport (= 3.1.0.rc5)
      bcrypt-ruby (~> 2.1.4)
      builder (~> 3.0.0)
      i18n (~> 0.6)
    activerecord (3.1.0.rc5)
      activemodel (= 3.1.0.rc5)
      activesupport (= 3.1.0.rc5)
      arel (~> 2.1.4)
      tzinfo (~> 0.3.29)
    activeresource (3.1.0.rc5)
      activemodel (= 3.1.0.rc5)
      activesupport (= 3.1.0.rc5)
    activesupport (3.1.0.rc5)
      multi_json (~> 1.0)
    arel (2.1.4)
    bcrypt-ruby (2.1.4-x86-mingw32)
    builder (3.0.0)
    coffee-rails (3.1.0.rc.5)
      actionpack (~> 3.1.0.rc1)
      coffee-script (>= 2.2.0)
      railties (~> 3.1.0.rc1)
      sprockets (>= 2.0.0.beta.9)
    coffee-script (2.2.0)
      coffee-script-source
      execjs
    coffee-script-source (1.1.2)
    diff-lcs (1.1.2)
    erubis (2.7.0)
    execjs (1.2.4)
      multi_json (~> 1.0)
    hike (1.2.0)
    i18n (0.6.0)
    jquery-rails (1.0.13)
      railties (~> 3.0)
      thor (~> 0.14)
    mail (2.3.0)
      i18n (>= 0.4.0)
      mime-types (~> 1.16)
      treetop (~> 1.4.8)
    mime-types (1.16)
    multi_json (1.0.3)
    nokogiri (1.5.0-x86-mingw32)
    polyglot (0.3.2)
    rack (1.3.2)
    rack-cache (1.0.2)
      rack (>= 0.4)
    rack-mount (0.8.2)
      rack (>= 1.0.0)
    rack-ssl (1.3.2)
      rack
    rack-test (0.6.1)
      rack (>= 1.0)
    rails (3.1.0.rc5)
      actionmailer (= 3.1.0.rc5)
      actionpack (= 3.1.0.rc5)
      activerecord (= 3.1.0.rc5)
      activeresource (= 3.1.0.rc5)
      activesupport (= 3.1.0.rc5)
      bundler (~> 1.0)
      railties (= 3.1.0.rc5)
    railties (3.1.0.rc5)
      actionpack (= 3.1.0.rc5)
      activesupport (= 3.1.0.rc5)
      rack-ssl (~> 1.3.2)
      rake (>= 0.8.7)
      rdoc (~> 3.4)
      thor (~> 0.14.6)
    rake (0.9.2)
    rdoc (3.9.2)
    rspec (2.0.0.beta.18)
      rspec-core (= 2.0.0.beta.18)
      rspec-expectations (= 2.0.0.beta.18)
      rspec-mocks (= 2.0.0.beta.18)
    rspec-core (2.0.0.beta.18)
    rspec-expectations (2.0.0.beta.18)
      diff-lcs (>= 1.1.2)
    rspec-mocks (2.0.0.beta.18)
    rspec-rails (2.0.0.beta.18)
      rspec (>= 2.0.0.beta.14)
      webrat (>= 0.7.0)
    sass (3.1.7)
    sass-rails (3.1.0.rc.5)
      actionpack (~> 3.1.0.rc1)
      railties (~> 3.1.0.rc1)
      sass (>= 3.1.4)
      sprockets (>= 2.0.0.beta.9)
    sprockets (2.0.0.beta.13)
      hike (~> 1.2)
      rack (~> 1.0)
      tilt (!= 1.3.0, ~> 1.1)
    sqlite3 (1.3.4-x86-mingw32)
    thor (0.14.6)
    tilt (1.3.2)
    treetop (1.4.10)
      polyglot
      polyglot (>= 0.3.1)
    tzinfo (0.3.29)
    uglifier (1.0.0)
      execjs (>= 0.3.0)
      multi_json (>= 1.0.2)
    webrat (0.7.3)
      nokogiri (>= 1.2.0)
      rack (>= 1.0)
      rack-test (>= 0.5.3)

PLATFORMS
  x86-mingw32

DEPENDENCIES
  coffee-rails (~> 3.1.0.rc)
  jquery-rails
  rails (= 3.1.0.rc5)
  rspec (= 2.0.0.beta.18)
  rspec-rails (= 2.0.0.beta.18)
  sass-rails (~> 3.1.0.rc)
  sqlite3
  uglifier

Answer 1

Try to remove your Gemfile.lock file and run bundle install again.