Revert "improve postgres escape sequence"

This reverts commit cc7a2c0.

Appraisals

@@ -1,5 +1,5 @@
 appraise 'activerecord-5.2' do
-  gem 'rails', '5.2.0'
+  gem 'activerecord', '5.2.0'
 end
 
 appraise 'activerecord-5.1' do

lib/acts_as_taggable_on/taggable/tagged_with_query/query_base.rb

@@ -48,7 +48,7 @@ def tags_match_type
 
     def escaped_tag(tag)
       tag = tag.downcase unless ActsAsTaggableOn.strict_case_match
-      ActsAsTaggableOn::Utils.escape_like(tag)
+      tag.gsub(/[!%_]/) { |x| '!' + x }
     end
 
     def adjust_taggings_alias(taggings_alias)

lib/acts_as_taggable_on/utils.rb

@@ -26,11 +26,7 @@ def like_operator
 
       # escape _ and % characters in strings, since these are wildcards in SQL.
       def escape_like(str)
-        str.gsub(/[!%_]/) { |x| escape_replacement + x }
-      end
-
-      def escape_replacement
-        using_postgresql? ? '\\' : '!'
+        str.gsub(/[!%_]/) { |x| '!' + x }
       end
     end
   end

spec/acts_as_taggable_on/utils_spec.rb

@@ -20,16 +20,4 @@
       expect(ActsAsTaggableOn::Utils.sha_prefix('puppies')).not_to eq(ActsAsTaggableOn::Utils.sha_prefix('kittens'))
     end
   end
-
-  describe '#escape_replacement' do
-    it 'should return ! when the adapter is not PostgreSQL' do
-      allow(ActsAsTaggableOn::Utils.connection).to receive(:adapter_name) { 'MySQL' }
-      expect(ActsAsTaggableOn::Utils.escape_replacement).to eq('!')
-    end
-
-    it 'should return \\ when the adapter is PostgreSQL' do
-      allow(ActsAsTaggableOn::Utils.connection).to receive(:adapter_name) { 'PostgreSQL' }
-      expect(ActsAsTaggableOn::Utils.escape_replacement).to eq('\\')
-    end
-  end
 end