Add slugs to updates.

- add column to Update table
 - add a slug to all old updates
 - use slugs in URLs
 - make update slugs unique (we'll need them for delete URLs)

app/models/update.rb

@@ -1,4 +1,6 @@
 class Update < ActiveRecord::Base
+  extend FriendlyId
+  friendly_id :subject, use: :slugged
   attr_accessible :body, :subject, :user_id
   belongs_to :user
   default_scope order("created_at desc")

db/migrate/20121214224227_add_slug_to_updates.rb

@@ -0,0 +1,6 @@
+class AddSlugToUpdates < ActiveRecord::Migration
+  def change
+    add_column :updates, :slug, :string
+    add_index :updates, :slug, unique: true
+  end
+end

db/migrate/20121214230336_give_old_updates_new_slugs.rb

@@ -0,0 +1,9 @@
+class GiveOldUpdatesNewSlugs < ActiveRecord::Migration
+  def up
+    Update.find_each(&:save)
+  end
+
+  # note: this is basically impossible to reverse without removing
+  # friendly_id, because friendly_id automatically updates the slug when
+  # you save the object.
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20121203034745) do
+ActiveRecord::Schema.define(:version => 20121214230336) do
 
   create_table "crops", :force => true do |t|
     t.string   "system_name",      :null => false
@@ -26,7 +26,7 @@ ActiveRecord::Schema.define(:version => 20121203034745) do
 
   create_table "gardens", :force => true do |t|
     t.string   "name",       :null => false
-    t.integer  "user_id"
+    t.integer  "user_id",    :null => false
     t.string   "slug",       :null => false
     t.datetime "created_at", :null => false
     t.datetime "updated_at", :null => false
@@ -48,9 +48,11 @@ ActiveRecord::Schema.define(:version => 20121203034745) do
     t.text     "body",       :null => false
     t.datetime "created_at", :null => false
     t.datetime "updated_at", :null => false
+    t.string   "slug"
   end
 
   add_index "updates", ["created_at", "user_id"], :name => "index_updates_on_created_at_and_user_id"
+  add_index "updates", ["slug"], :name => "index_updates_on_slug", :unique => true
 
   create_table "users", :force => true do |t|
     t.string   "email",                  :default => "", :null => false

spec/models/update_spec.rb

@@ -6,4 +6,10 @@ describe Update do
     Update.create! :subject => "second entry", :body => "blah", :user_id => 1
     Update.first.subject.should == "second entry"
   end
+
+  it "should have a slug" do
+    update = Update.create! :subject => "slugs are nasty",
+      :body => "They leave slime everywhere", :user_id => 1
+    update.slug.should == "slugs-are-nasty"
+  end
 end