Add documentation updates

Document the new configuration options, and change the URL to the
public-facing url on gerrit.googlesource.com

Change-Id: I99f8e3a139e7b57c95564e4d920ac79150379e2c

BUCK

diff --git a/BUCK b/BUCK
index 3351729..367d677 100644
--- a/BUCK
+++ b/BUCK
@@ -4,7 +4,7 @@
   resources = glob(['src/main/resources/**/*']),
   manifest_entries = [
     'Implementation-Title: Ref Protection plugin',
-    'Implementation-URL: http://review-plus.sonyericsson.net/#/admin/projects/gerrit/plugins/ref-protection',
+    'Implementation-URL: http://gerrit.googlesource.com/plugins/ref-protection',
     'Gerrit-PluginName: ref-protection',
     'Gerrit-Module: com.googlesource.gerrit.plugins.refprotection.RefProtectionModule'
   ],

src/main/resources/Documentation/about.md

diff --git a/src/main/resources/Documentation/about.md b/src/main/resources/Documentation/about.md
index c681000..4d2d541 100644
--- a/src/main/resources/Documentation/about.md
+++ b/src/main/resources/Documentation/about.md
@@ -1,10 +1,24 @@
 Ref protection plugin.
 
-Protects against commits being lost by creating backups of deleted refs under
-the `refs/backups/` namespace.
+Protects against commits being lost by creating backups of deleted refs 
+(or non-fast-forward commits) under the `refs/backups/` namespace.
+
+Branch deletion protection can be disabled by setting 
+`plugin.ref-protection.protectDeleted false` in `gerrit.config`.
+Similarly, non-fast-forward update protection can be disabled with
+`plugin.ref-protection.protectFastForward false`.
 
 Branches under `refs/heads/` that are deleted or rewritten are backed up
-as `refs/backups/heads/branch-name-YYYYMMDD-HHmmss`.
+as `refs/backups/heads/branch-name-YYYYMMDD-HHmmss` by default, or as
+sequentially increasing numbers under `refs/backups/heads/branch-name/#`
+by setting `plugin.ref-protection.useTimestamp false`.
 
 Tags under `refs/tags/` that are deleted are backed up (as branches) as
-`refs/backups/tags/tag-name-YYYYMMDD-HHmmss`.
+`refs/backups/tags/tag-name-YYYYMMDD-HHmmss` or as sequentially
+increasing numbers under `refs/backups/tags/branch-name/#` using the same
+`plugin.ref-protection.useTimestamp` setting.
+
+By default, the backups are created as branches.  Optionally, they may
+be created as tags, containing information about the original ref that
+was changed, as well as the user that performed the change.  This can
+be enabled by setting `plugin.ref-protection.createTag true`.