exists? to support ids which are strings

lib/active_hash/base.rb

@@ -113,7 +113,7 @@ def exists?(args = :none)
         elsif args.is_a?(Hash)
           all.where(args).present?
         else
-          all.where(id: args.to_i).present?
+          all.where(id: args.to_s).present?
         end
       end
 

spec/active_hash/base_spec.rb

@@ -1246,6 +1246,16 @@ def continent
         end
       end
     end
+
+    context "when ids are strings" do
+      before do
+        Country.all.each { |c| c.id = c.name }
+      end
+
+      it "return true" do
+        expect(Country.exists?("Canada")).to be_truthy
+      end
+    end
   end
 
   describe "#method_missing" do