Private methods indentation

We should discuss code convention about indentation private methods in classes. We have two common conventions.

First one:

``` ruby
class Foo
  def public_method
  end

  private

    def private_method
    end
end
```

Second one:

``` ruby
class Bar
  def public_method
  end

private

  def private_method
  end
end
```

Also I propose to add one blank line before `private` word and one after.
