Refactor zones

- Rename "zonefile_setting" to "zone"
- Remove version

#475

app/controllers/admin/dns/zones_controller.rb

@@ -0,0 +1,64 @@
+module Admin
+  module DNS
+    class ZonesController < AdminController
+      #load_and_authorize_resource(class: DNS::Zone)
+      skip_authorization_check
+      before_action :load_zone, only: %i[edit update destroy]
+
+      def index
+        @zones = ::DNS::Zone.all
+      end
+
+      def new
+        @zone = ::DNS::Zone.new
+      end
+
+      def create
+        @zone = ::DNS::Zone.new(zone_params)
+
+        if @zone.save
+          flash[:notice] = t('.created')
+          redirect_to_index
+        else
+          render :new
+        end
+      end
+
+      def edit
+        @zone = ::DNS::Zone.find(params[:id])
+      end
+
+      def update
+        if @zone.update(zone_params)
+          flash[:notice] = t('.updated')
+          redirect_to_index
+        else
+          render :edit
+        end
+      end
+
+      def destroy
+        @zone.destroy!
+        flash[:notice] = t('.destroyed')
+        redirect_to_index
+      end
+
+      private
+
+      def load_zone
+        @zone = ::DNS::Zone.find(params[:id])
+      end
+
+      def zone_params
+        params.require(:zone).permit(
+          :origin, :ttl, :refresh, :retry, :expire, :minimum_ttl, :email,
+          :master_nameserver, :ns_records, :a_records, :a4_records
+        )
+      end
+
+      def redirect_to_index
+        redirect_to admin_zones_url
+      end
+    end
+  end
+end