Merge pull request #2425 from rspec/remove-monkey-patching

Add a check to support both RSpec 3 & 4

Author: JonRowe

lib/rspec/rails/matchers/relation_match_array.rb

@@ -1,3 +1,3 @@
-if defined?(ActiveRecord::Relation)
+if defined?(ActiveRecord::Relation) && defined?(RSpec::Matchers::BuiltIn::OperatorMatcher) # RSpec 4 removed OperatorMatcher
   RSpec::Matchers::BuiltIn::OperatorMatcher.register(ActiveRecord::Relation, '=~', RSpec::Matchers::BuiltIn::ContainExactly)
 end