Do not require that validation attributes be specified as symbols

activemodel/lib/active_model/validations/validates.rb

@@ -84,7 +84,6 @@ def validates(*attributes)
         validations = defaults.slice!(:if, :unless, :on, :allow_blank, :allow_nil)
 
         raise ArgumentError, "You need to supply at least one attribute" if attributes.empty?
-        raise ArgumentError, "Attribute names must be symbols" if attributes.any?{ |attribute| !attribute.is_a?(Symbol) }
         raise ArgumentError, "You need to supply at least one validation" if validations.empty?
 
         defaults.merge!(:attributes => attributes)
@@ -118,4 +117,4 @@ def _parse_validates_options(options) #:nodoc:
       end
     end
   end
-end
\ No newline at end of file
+end

activemodel/test/cases/validations/validates_test.rb

@@ -21,6 +21,17 @@ def test_validates_with_built_in_validation
     assert_equal ['is not a number'], person.errors[:title]
   end
 
+  def test_validates_with_attribute_specified_as_string
+    Person.validates "title", :numericality => true
+    person = Person.new
+    person.valid?
+    assert_equal ['is not a number'], person.errors[:title]
+
+    person = Person.new
+    person.title = 123
+    assert person.valid?
+  end
+
   def test_validates_with_built_in_validation_and_options
     Person.validates :salary, :numericality => { :message => 'my custom message' }
     person = Person.new