Adapt plugin sharing (#1553)

* Reuse old package config

* Add plugin config shape

* Add ButtonGroup to core components

* List all sharing sites

* Displaying buttons from config

* First iteration of Dropdown component (need CSS)

* Using Dropdown for sharing button

* Create HotKeys component

* Move Backdrop to its own file

* Trying a cleaner API for Dropdown

* Add README.md

* livereload: Add missing gitbook-plugin dependency

* sharing: Now use Immutable state

* sharing: Adapt quickly to new Dropdown

* sharing: Fix sharing from dropdown

1 files changed, 38 insertions, 0 deletions

diff --git a/packages/gitbook-plugin-sharing/README.md b/packages/gitbook-plugin-sharing/README.md
new file mode 100644
index 0000000..28ae0d4
--- /dev/null
+++ b/packages/gitbook-plugin-sharing/README.md
@@ -0,0 +1,38 @@
+# plugin-sharing
+
+This plugin adds sharing buttons in the GitBook website toolbar to share book on social networks.
+
+### Disable this plugin
+
+This is a default plugin and it can be disabled using a `book.json` configuration:
+
+```
+{
+    plugins: ["-sharing"]
+}
+```
+
+### Configuration
+
+This plugin can be configured in the `book.json`:
+
+Default configuration is:
+
+```js
+{
+    "pluginsConfig": {
+        "sharing": {
+            "facebook": true,
+            "twitter": true,
+            "google": false,
+            "weibo": false,
+            "instapaper": false,
+            "vk": false,
+            "all": [
+                "facebook", "google", "twitter",
+                "weibo", "instapaper"
+            ]
+        }
+    }
+}
+```