Fix name and id generation for hidden_field

Use the proper rails naming convention for id/name when using bootstrap_form_tag

lib/bootstrap_form/form_builder.rb

@@ -108,6 +108,16 @@ def time_zone_select_with_bootstrap(method, priority_zones = nil, options = {},
 
     bootstrap_method_alias :time_zone_select
 
+    def hidden_field_with_bootstrap(method, options = {})
+      if acts_like_form_tag
+        options[:id] ||= method.to_s
+        options[:name] ||= method.to_s
+      end
+      hidden_field_without_bootstrap(method, options)
+    end
+
+    bootstrap_method_alias :hidden_field
+
     def check_box_with_bootstrap(name, options = {}, checked_value = "1", unchecked_value = "0", &block)
       options = options.symbolize_keys!
       options = convert_form_tag_options(name, options) if acts_like_form_tag

test/bootstrap_form_test.rb

@@ -58,6 +58,11 @@ def setup
     assert_equal expected, bootstrap_form_tag(url: '/users') { |f| f.radio_button :misc, 1 }
   end
 
+  test "bootstrap_form_tag use proper rails naming convention for hidden field" do
+    expected = %{<form accept-charset=\"UTF-8\" action=\"/users\" method=\"post\" role=\"form\"><div style=\"margin:0;padding:0;display:inline\"><input name=\"utf8\" type=\"hidden\" value=\"&#x2713;\" /></div><input id=\"email\" name=\"email\" type=\"hidden\" value=\"test@yahoo.com\" /></form>}
+    assert_equal expected, bootstrap_form_tag(url: '/users') { |f| f.hidden_field :email, value: 'test@yahoo.com' }
+  end
+
   test "errors display correctly and inline_errors are turned off by default when label_errors is true" do
     @user.email = nil
     @user.valid?