09_speedup "ruby_dep requires Ruby version >= 2.2.5, ~> 2.2."

[hirokihokari]

When I pull 09_speedup branch for use in Chap 11, bundle install didn't succeed.

The bundler error suggested "it might be Gemfile.lock corruption" so I removed the file and tried bundle install again, and this error showed up:

In Gemfile:
  guard-rspec was resolved to 4.3.1, which depends on
    guard was resolved to 2.14.1, which depends on
      listen was resolved to 3.1.5, which depends on
        ruby_dep

and

ruby_dep requires Ruby version >= 2.2.5, ~> 2.2.

and .ruby-version specifies 2.1.1

If I comment guard-rspec in Gemfile, the command succeeds.

Two choices:

1. remove guard-rspec => No
2. Change the ruby version to ~>2.2 => can't evaluate the influence of this

Does anyone have suggestions?

[ruralocity]

For the purposes of getting through the tutorial, you could also try locking down to an older version of guard, and add that to the Gemfile:

gem 'guard', '2.6.1'