[Fix #12] Allow passing boolean literals to touch

The `Rails/SkipsModelValidations` cop currently incorrectly registers an
offense for the `touch` method from Shoulda Matchers' associations DSL:

    it { is_expected.to belong_to(:user).touch(true) }

Active Record's `touch` method accepts attribute names, so we can treat
`touch` calls that pass boolean literal arguments as false positives.

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## master (unreleased)
 
+### Bug fixes
+
+* [#12](https://github.com/rubocop-hq/rubocop-rails/issues/12): Fix a false positive for `Rails/SkipsModelValidations` when passing a boolean literal to `touch`. ([@eugeneius][])
+
 ## 2.5.2 (2020-04-09)
 
 ### Bug fixes

lib/rubocop/cop/rails/skips_model_validations.rb

@@ -50,7 +50,10 @@ class SkipsModelValidations < Cop
                                     update_counters].freeze
 
         def_node_matcher :good_touch?, <<~PATTERN
-          (send (const nil? :FileUtils) :touch ...)
+          {
+            (send (const nil? :FileUtils) :touch ...)
+            (send _ :touch {true false})
+          }
         PATTERN
 
         def on_send(node)

spec/rubocop/cop/rails/skips_model_validations_spec.rb

@@ -35,6 +35,14 @@
     it 'accepts FileUtils.touch' do
       expect_no_offenses("FileUtils.touch('file')")
     end
+
+    it 'accepts touch with literal true' do
+      expect_no_offenses('belongs_to(:user).touch(true)')
+    end
+
+    it 'accepts touch with literal false' do
+      expect_no_offenses('belongs_to(:user).touch(false)')
+    end
   end
 
   context 'with methods that require at least an argument' do