安装mysqltopostgres-0.2.20.gem时出错

Question

我安装了一个红宝石宝石： mysqltopostgres-0.2.20.gem 当我试图运行它时，我收到了这个错误：

You have already activated test-unit 2.5.5, but your Gemfile requires test-unit 3.1.9. Using bundle exec may solve this. (Gem::LoadError)
    from /usr/lib/ruby/vendor_ruby/bundler/runtime.rb:19:in `setup'
    from /usr/lib/ruby/vendor_ruby/bundler.rb:120:in `setup'
    from /usr/lib/ruby/vendor_ruby/bundler/setup.rb:7:in `<top (required)>'
    from /usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
    from /usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
    from /var/lib/gems/1.9.1/gems/mysqltopostgres-0.3.0/bin/mysqltopostgres:5:in `<top (required)>'
    from /usr/local/bin/mysqltopostgres:23:in `load'
    from /usr/local/bin/mysqltopostgres:23:in `<main>'

我怀疑Gemfile.lock文件出了问题，但无法理解它究竟是什么。 以下是Gemfile.lock的内容：

GEM
  remote: https://rubygems.org/
  specs:
    addressable (2.4.0)
    builder (3.2.2)
    descendants_tracker (0.0.4)
      thread_safe (~> 0.3, >= 0.3.1)
    faraday (0.9.2)
      multipart-post (>= 1.2, < 3)
    git (1.3.0)
    github_api (0.14.0)
      addressable (~> 2.4.0)
      descendants_tracker (~> 0.0.4)
      faraday (~> 0.8, < 0.10)
      hashie (>= 3.4)
      oauth2
    hashie (3.4.4)
    highline (1.7.8)
    jeweler (2.1.1)
      builder
      bundler (>= 1.0)
      git (>= 1.2.5)
      github_api
      highline (>= 1.6.15)
      nokogiri (>= 1.5.10)
      rake
      rdoc
      semver
    json (1.8.3)
    jwt (1.5.1)
    mini_portile2 (2.0.0)
    multi_json (1.12.1)
    multi_xml (0.5.5)
    multipart-post (2.0.0)
    mysql-pr (2.9.11)
    nokogiri (1.6.7.2)
      mini_portile2 (~> 2.0.0.rc2)
    oauth2 (1.1.0)
      faraday (>= 0.8, < 0.10)
      jwt (~> 1.0, < 1.5.2)
      multi_json (~> 1.3)
      multi_xml (~> 0.5)
      rack (>= 1.2, < 3)
    pg (0.18.4)
    postgres-pr (0.7.0)
    power_assert (0.3.0)
    rack (1.6.4)
    rake (10.5.0)
    rdoc (4.2.2)
      json (~> 1.4)
    semver (1.0.1)
    test-unit (3.1.9)
      power_assert
    thread_safe (0.3.5)

PLATFORMS
  ruby

DEPENDENCIES
  activerecord
  activerecord-jdbc-adapter
  activerecord-jdbcpostgresql-adapter
  jdbc-postgres
  jeweler (~> 2.0)
  mysql-pr (~> 2.9)
  pg (~> 0.18)
  postgres-pr (~> 0.6)
  rake (~> 10.3)
  test-unit

请让我知道您对此的看法？