error

Bundler could not find compatible versions for gem "multi_json":
  In Gemfile:
    community_engine (>= 0) ruby depends on
      multi_json (~> 1.0.0) ruby

    uglifier (>= 1.0.3) ruby depends on
      multi_json (1.3.6)

Gemfile

gem 'rails', '3.2.6'
gem 'sqlite3'
gem 'json'
group :assets do
  gem 'sass-rails',   '~> 3.2.3'
  gem 'coffee-rails', '~> 3.2.1'
  gem 'uglifier', '>= 1.0.3'
end
gem 'jquery-rails'
gem 'community_engine', :github => 'bborn/communityengine', :branch => 'rails3'

doubt

always gives the same error despite of following all the instructions in the README FILE of the community engine