better revision history

db/migrate/20131209091702_create_post_revisions.rb

@@ -0,0 +1,25 @@
+class CreatePostRevisions < ActiveRecord::Migration
+  def up
+    create_table :post_revisions do |t|
+      t.belongs_to :user
+      t.belongs_to :post
+      t.text :modifications
+      t.integer :number
+      t.timestamps
+    end
+
+    execute "INSERT INTO post_revisions (user_id, post_id, modifications, number, created_at, updated_at)
+             SELECT user_id, versioned_id, modifications, number, created_at, updated_at
+             FROM   versions
+             WHERE  versioned_type = 'Post'"
+
+    change_table :post_revisions do |t|
+      t.index :post_id
+      t.index [:post_id, :number]
+    end
+  end
+
+  def down
+    drop_table :post_revisions
+  end
+end

db/migrate/20131209091742_create_topic_revisions.rb

@@ -0,0 +1,25 @@
+class CreateTopicRevisions < ActiveRecord::Migration
+  def up
+    create_table :topic_revisions do |t|
+      t.belongs_to :user
+      t.belongs_to :topic
+      t.text :modifications
+      t.integer :number
+      t.timestamps
+    end
+
+    execute "INSERT INTO topic_revisions (user_id, topic_id, modifications, number, created_at, updated_at)
+             SELECT user_id, versioned_id, modifications, number, created_at, updated_at
+             FROM   versions
+             WHERE  versioned_type = 'Topic'"
+
+    change_table :topic_revisions do |t|
+      t.index :topic_id
+      t.index [:topic_id, :number]
+    end
+  end
+
+  def down
+    drop_table :topic_revisions
+  end
+end

db/migrate/20131210234530_rename_version_column.rb

@@ -0,0 +1,9 @@
+class RenameVersionColumn < ActiveRecord::Migration
+
+  def change
+    add_column :posts, :version, :integer, default: 1, null: false
+    execute "UPDATE posts SET version = cached_version"
+    remove_column :posts, :cached_version
+  end
+
+end