fix redundant `self`
bundle update rspec
Convert specs to RSpec 2.99.0 syntax with Transpec

This conversion is done by Transpec 2.2.1 with the following command:
    transpec --no-explicit-spec-type

* 22 conversions
    from: it { should ... }
      to: it { is_expected.to ... }

* 15 conversions
    from: obj.should
      to: expect(obj).to

* 2 conversions
    from: obj.stub!(:message)
      to: allow(obj).to receive(:message)

For more details: https://github.com/yujinakayama/transpec#supported-conversions
bump rspec-rails to 3.0.0
remove `require 'rspec/autorun'`

- deprecation warning message is the following
Requiring `rspec/autorun` when running RSpec via the `rspec` command is deprecated.