Make DB seed idempotent.

db/seeds.rb

@@ -5,7 +5,7 @@ Refinery::User.find(:all).each do |user|
   end
 end if defined?(Refinery::User)
 
-if defined?(Refinery::Page)
+if defined?(Refinery::Page) and !Refinery::Page.exists?(:link_url => '/blog')
   page = Refinery::Page.create(
     :title => "Blog",
     :link_url => "/blog",

spec/lib/refinery/blog/engine_spec.rb

@@ -3,12 +3,23 @@ require 'spec_helper'
 module Refinery
   module Blog
     describe Engine do
-      let(:activity) do
+      describe "plugin activity" do
-        Refinery::Plugins.registered.find_by_name("refinerycms_blog").activity.first
+        let(:activity) do
+          Refinery::Plugins.registered.find_by_name("refinerycms_blog").activity.first
+        end
+
+        it "sets the correct path for activity entries" do
+          activity.url.should eq("edit_refinery_admin_blog_posts_path")
+        end
       end
 
-      it "sets the correct path for activity entries" do
+      describe ".load_seed" do
-        activity.url.should eq("edit_refinery_admin_blog_posts_path")
+        it "is idempotent" do
+          Refinery::Blog::Engine.load_seed
+          Refinery::Blog::Engine.load_seed
+
+          Refinery::Page.where(:link_url => '/blog').count.should eq(1)
+        end
       end
     end
   end