Add regression spec for #496 and update changelog.

Follow-up to previous commit a3d6f2c.

CHANGELOG.md

@@ -1,5 +1,17 @@
 # Change Log
 
+## Master (unreleased)
+
+*   Fix a regression
+    ([#496](https://github.com/activerecord-hackery/ransack/issues/496)) caused
+    by [ee571fe](https://github.com/activerecord-hackery/ransack/commit/ee571fe)
+    where passing a multi-parameter attribute (i.e. `date_select`) raised
+    `RuntimeError: can't add a new key into hash during iteration`, and add a
+    regression spec for the issue.
+
+    *Nate Berkopec*, *Jon Atack*
+
+
 ## Version 1.6.2 - 2015-01-14
 
 *   Fix a regression

spec/ransack/adapters/active_record/base_spec.rb

@@ -152,6 +152,18 @@ module Ransack
             s = Person.ransack('')
           end
 
+          it "should function correctly with a multi-parameter attribute" do
+            date = Date.current
+            s = Person.ransack(
+              { "created_at_gteq(1i)" => date.year,
+                "created_at_gteq(2i)" => date.month,
+                "created_at_gteq(3i)" => date.day
+              }
+            )
+            expect(s.result.to_sql).to match />=/
+            expect(s.result.to_sql).to match date.to_s
+          end
+
           it "should function correctly when using fields with dots in them" do
             s = Person.ransack(:email_cont => "example.com")
             expect(s.result.exists?).to be true