Correct section on checking out tags

This commit updates the section on checking out tags by replacing
the old text saying you can't really do it with a short paragraph
explaining how to do it.

Author: Thomas Hartmann

book/02-git-basics/sections/tagging.asc

@@ -211,13 +211,25 @@ Now, when someone else clones or pulls from your repository, they will get all y
 
 ==== Checking out Tags
 
-You can't really check out a tag in Git, since they can't be moved around.
-If you want to put a version of your repository in your working directory that looks like a specific tag, you can create a new branch at a specific tag with  `git checkout -b [branchname] [tagname]`:
+You can check out a tag through the `git checkout` command the same way you would with a commit:
 
 [source,console]
 ----
-$ git checkout -b version2 v2.0.0
-Switched to a new branch 'version2'
-----
+$ git checkout 2.0.0
+Note: checking out '2.0.0'.
+
+You are in 'detached HEAD' state. You can look around, make experimental
+changes and commit them, and you can discard any commits you make in this
+state without impacting any branches by performing another checkout.
+
+If you want to create a new branch to retain commits you create, you may
+do so (now or later) by using -b with the checkout command again. Example:
+
+  git checkout -b <new-branch-name>
+
+HEAD is now at 99ada87... Merge pull request #89 from schacon/appendix-final
 
-Of course if you do this and do a commit, your `version2` branch will be slightly different than your `v2.0.0` tag since it will move forward with your new changes, so do be careful.
+$ git checkout 2.0-beta-0.1
+Previous HEAD position was 99ada87... Merge pull request #89 from schacon/appendix-final
+HEAD is now at df3f601... add atlas.json and cover image
+----