1 files changed, 9 insertions, 2 deletions
diff --git a/activerecord/lib/active_record/associations/builder/singular_association.rb b/activerecord/lib/active_record/associations/builder/singular_association.rb
index e655c389a6..1369212837 100644
--- a/activerecord/lib/active_record/associations/builder/singular_association.rb
+++ b/activerecord/lib/active_record/associations/builder/singular_association.rb
@@ -2,8 +2,8 @@
 
 module ActiveRecord::Associations::Builder
   class SingularAssociation < Association #:nodoc:
-    def valid_options
-      super + [:remote, :dependent, :primary_key, :inverse_of]
+    def self.valid_options(options)
+      super + [:dependent, :primary_key, :inverse_of, :required]
     end
 
     def self.define_accessors(model, reflection)
@@ -27,5 +27,12 @@ module ActiveRecord::Associations::Builder
         end
       CODE
     end
+
+    def self.define_validations(model, reflection)
+      super
+      if reflection.options[:required]
+        model.validates_presence_of reflection.name
+      end
+    end
   end
 end