Updated README with new auth/upgrade instructions.

README.textile

@@ -26,20 +26,57 @@ h2. Quick Start
   rails server    # Start the server
   # Load http://localhost:3000/admin in your browser</code></pre>
 
-Or for bonus points, fork "enki at github":http://github.com/xaviershay/enki/tree/master and clone that instead.
+Or for bonus points, fork "enki at github":https://github.com/xaviershay/enki/tree/master and clone that instead.
 
 h2. More info
 
 Enki is a compact, easily extendable base for your blog. It does this by being highly opinionated, for example:
 
-* Public facing views should adhere to standards (XHTML(eXtensible Hypertext Markup Language), Atom)
+* Public facing views should adhere to standards (HTML5, Atom)
 * /yyyy/mm/dd/post-title is a good URL for your posts
 * Live comment preview should be provided by default
 * Google does search better than you or I
 * You don't need a plugin system when you've got decent source control
-* If you're not using OpenID you're a chump
+* If you're not using something more than just a basic username/password, you're a chump
 * Hacking code is the easiest way to customize something
 
+h2. Setting up authentication
+
+Enki uses "OmniAuth":https://github.com/intridea/omniauth for authentication. By default Enki supports "Google OpenID Connect (OAuth 2.0 for Login)":https://developers.google.com/identity/protocols/OpenIDConnect via the "omniauth-google-oauth2":https://github.com/zquestz/omniauth-google-oauth2 strategy and OpenID 2.0 via the "omniauth-openid":https://github.com/intridea/omniauth-openid strategy. Should you wish to use a different form of authentication, you can implement any of the "available OmniAuth strategies":https://github.com/intridea/omniauth/wiki/List-of-Strategies, or write your own strategy.
+
+h3. Using Google OpenID Connect for authentication
+
+You will need a Google account, then:
+
+* Go to "https://console.developers.google.com":https://console.developers.google.com
+* Select (or create) your project
+* Click 'APIs & auth'
+* Make sure "Contacts API" and "Google+ API" are enabled.
+* Go to the Consent Screen, and provide an 'Email address' and 'Product name'
+* Wait 10 minutes for changes to take effect.
+* Click on 'Credentials' under 'APIs & auth' and take note of your 'Client ID' and 'Client secret'
+
+Create a new file called <code>google_oauth2.yml</code> in your <code>config</code> directory, add your 'Client ID' and 'Client secret' to the file thusly:
+
+<pre><code>GOOGLE_CLIENT_ID: 'ADD_YOUR_CLIENT_ID_HERE'
+GOOGLE_CLIENT_SECRET: 'ADD_YOUR_CLIENT_SECRET_HERE'
+</code></pre>
+
+If you are deploying to Heroku, you will need to set the above as <code>ENV</code> variables instead of using <code>google_oauth2.yml</code>. For example:
+
+<pre><code>$ heroku config:set GOOGLE_CLIENT_ID=my_client_id
+$ heroku config:set GOOGLE_CLIENT_SECRET=my_client_secret</code></pre>
+
+Open up <code>config/enki.yml</code> and make sure that the <code>google_oauth2_email</code> value matches the email address of your Google OpenID Connect identity.
+
+h3. Using OpenID 2.0 for authentication
+
+Open up <code>config/enki.yml</code> and make sure that the <code>open_id</code> value(s) match one or more of your OpenID identity URLs.
+
+h2. Upgrading to Enki 2015
+
+As of April 2015, Enki no longer uses the "open_id_authentication":https://github.com/Velir/open_id_authentication gem. Commit "ec85a":https://github.com/xaviershay/enki/commit/ec85aef26ee82f17e8225be5cbe03ea459d1f112 contains database migrations that remove both tables used by open_id_authentication and add a new table to store OmniAuth response information. Should you wish to keep any data that you may have currently stored in either the open_id_authentication_nonces or open_id_authentication_associations tables, retrieve this information before you run <code>rake db:migrate</code> to upgrade your Enki install.
+
 h2. URL path prefix
 
 Enki can run your blog with a URL path prefix.  For example, you can run it at example.com/*blog* instead of blog.example.com.  You can do so with the RAILS_RELATIVE_URL_ROOT environment variable, set either before starting the server or in config/application.rb before Enki::Application.  Uncommenting this line in config/application.rb will enable this behavior in all environments:
@@ -56,7 +93,7 @@ Enki embodies much of the philosophy of SimpleLog, but does so in a style that i
 
 h2. Compatibility
 
-Uses Ruby 1.9.3 or newer and Rails 4. Runs on MySQL or Postgres. Works on heroku.
+Uses Ruby 1.9.3 or newer and Rails 4. Runs on MySQL or Postgres. Works on Heroku.
 
 h2. Contributors, these guys rock