Add include_blank option to enum field

app/views/fields/enum/_form.html.erb

@@ -26,6 +26,6 @@ By default, the input is a select field for the enum attributes.
     end,
     f.object.public_send(field.attribute.to_s)
   ),
-  { include_blank: !f.object.class.validators_on(field.attribute.to_s).map(&:class).include?(ActiveRecord::Validations::PresenceValidator) },
+  { include_blank: field.include_blank_option || !f.object.class.validators_on(field.attribute.to_s).map(&:class).include?(ActiveRecord::Validations::PresenceValidator) },
   field.html_options) %>
 </div>

lib/administrate/field/enum.rb

@@ -12,6 +12,10 @@ def html_options
         options[:html] || {}
       end
 
+      def include_blank_option
+        options.fetch(:include_blank, false)
+      end
+
       class Engine < ::Rails::Engine
       end
     end

spec/lib/administrate/field/enum_spec.rb

@@ -12,6 +12,24 @@
     end
   end
 
+  describe '.include_blank' do
+    it 'is false by default' do
+      page = :show
+
+      field = Administrate::Field::Enum.new(:status, 'status', page)
+
+      expect(field.include_blank_option).to be_falsy
+    end
+
+    it 'can override include_blank_option' do
+      page = :show
+
+      field = Administrate::Field::Enum.with_options(include_blank: true).new(:status, 'status', page)
+
+      expect(field.include_blank_option).to be_truthy
+    end
+  end
+
   describe '#html_options' do
     it 'returns a hash of :html options' do
       page = :show