Add support to build the plugin with BUCK

The following command from the gerrit directory can be used
to build the plugin with buck:

buck build plugins/avatars/external:avatars-external

Add "about" and "build" sections to the Documentation to make
info page more uniform with other plugins.

Change-Id: I076bed94edb704ba4e8fca14844b230d26518010
diff --git a/BUCK b/BUCK
new file mode 100644
index 0000000..8e99cda
--- /dev/null
+++ b/BUCK
@@ -0,0 +1,11 @@
+gerrit_plugin(
+  name = 'avatars-external',
+  srcs = glob(['src/main/java/**/*.java']),
+  resources = glob(['src/main/resources/**/*']),
+  manifest_entries = [
+    'Gerrit-PluginName: avatars-external',
+    'Implementation-Title: External Avatar plugin',
+    'Implementation-URL: https://gerrit-review.googlesource.com/#/admin/projects/plugins/avatars/external',
+    'Gerrit-AvatarProvider: com.googlesource.gerrit.plugins.avatars.external.ExternalUrlAvatarProvider',
+  ],
+)
diff --git a/src/main/resources/Documentation/about.md b/src/main/resources/Documentation/about.md
new file mode 100644
index 0000000..737ed5c
--- /dev/null
+++ b/src/main/resources/Documentation/about.md
@@ -0,0 +1 @@
+This plugin allows to use an external url to load the avatar images from.
diff --git a/src/main/resources/Documentation/build.md b/src/main/resources/Documentation/build.md
new file mode 100644
index 0000000..ab2650f
--- /dev/null
+++ b/src/main/resources/Documentation/build.md
@@ -0,0 +1,28 @@
+Build
+=====
+
+This plugin can be built with Buck and Maven.
+
+
+Buck
+----
+
+From gerrit source directory:
+
+```
+buck build plugins/avatars/external:avatars-external
+```
+
+You will find the `avatars-external.jar` file in `buck-out/gen/plugins/avatars/external`.
+
+
+Maven
+-----
+
+From the plugin directory:
+
+```
+mvn clean package
+```
+
+You will find the `external-url-avatar-provider-1.0-SNAPSHOT.jar` file in `target` directory in the plugin directory.
diff --git a/src/main/resources/Documentation/config.md b/src/main/resources/Documentation/config.md
index 367af0e..106586a 100644
--- a/src/main/resources/Documentation/config.md
+++ b/src/main/resources/Documentation/config.md
@@ -1,18 +1,18 @@
 External URL Avatar Plugin Configuration
-=========================
+========================================
 
-This plugin allows to use an own web service to load the avatar images from.
 
 Options:
 
-* `avatar.url` - the location of avatar images containing `%s`, which will then be replaced by the `username`. Required.
-* `avatar.changeUrl` - the URL shown in Gerrit's user settings to tell the user, where the avatar can be changed. Optional. 
+  * `avatar.url` - the location of avatar images containing `%s`, which will then be replaced by the `username`. Required.
+  * `avatar.changeUrl` - the URL shown in Gerrit's user settings to tell the user, where the avatar can be changed. Optional.
 
 Example (to be added to `etc/gerrit.config`):
 
+```
     [avatar]
         url = http://example.org/avatars/%s.jpg
         changeUrl = http://example.org/account.html
+```
 
-Please note that `http://` URLs will be automatically rewritten to `https://`, if `gerrit.canonicalWebUrl` uses HTTPS. 
-        
\ No newline at end of file
+Please note that `http://` URLs will be automatically rewritten to `https://`, if `gerrit.canonicalWebUrl` uses HTTPS.
\ No newline at end of file