Bundler找不到gem“spree_core”的兼容版本

我正在尝试安装spree_braintree gem以将braintree网关与spree 3.0.1集成 . 当我运行“bundle install”时，我收到此错误“Bundler无法找到gem的兼容版本”spree_core“” . 这是我的Gemfile .

source 'https://rubygems.org'
    # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
    gem 'rails', '4.2.1'
    # Use sqlite3 as the database for Active Record
    gem 'sqlite3'
    # Use SCSS for stylesheets
    gem 'sass-rails', '~> 5.0'
    # Use Uglifier as compressor for JavaScript assets
    gem 'uglifier', '>= 1.3.0'
    # Use CoffeeScript for .coffee assets and views
    gem 'coffee-rails', '~> 4.1.0'
    # See https://github.com/rails/execjs#readme for more supported runtimes
    # gem 'therubyracer', platforms: :ruby

    # Use jquery as the JavaScript library
    gem 'jquery-rails'
    # Turbolinks makes following links in your web application faster. Read more: https://github.com/rails/turbolinks
    gem 'turbolinks'
    # Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
    gem 'jbuilder', '~> 2.0'
    # bundle exec rake doc:rails generates the API under doc/api.
    gem 'sdoc', '~> 0.4.0', group: :doc

    # Use ActiveModel has_secure_password
    # gem 'bcrypt', '~> 3.1.7'

    # Use Unicorn as the app server
    # gem 'unicorn'

    # Use Capistrano for deployment
    # gem 'capistrano-rails', group: :development

    group :development, :test do
      # Call 'byebug' anywhere in the code to stop execution and get a debugger console
      gem 'byebug'

      # Access an IRB console on exception pages or by using  in views
      gem 'web-console', '~> 2.0'

      # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
      gem 'spring'
    end


    gem 'spree', '3.0.1'
    gem 'spree_gateway', github: 'spree/spree_gateway', branch: '3-0-stable'
    gem 'spree_auth_devise', github: 'spree/spree_auth_devise', branch: '3-0-stable'
    gem 'spree_braintree', :git => 'git://github.com/rortechie/spree-braintree.git

'

Error message:
<pre>
Bundler could not find compatible versions for gem "spree_core":
  In Gemfile:
    spree_braintree (>= 0) ruby depends on
      spree_core (~> 1.0.0) ruby

    spree (= 3.0.1) ruby depends on
      spree_sample (= 3.0.1) ruby depends on
        spree_core (3.0.1)

我也尝试删除Gemfile.lock并运行bundle install但它没有用 . 我使用的是ruby 2.2.2和rails 4.2.1 .