Add software version to the api

docs/json-rpc-api.markdown

@@ -109,6 +109,34 @@ Array
 Procedures
 ----------
 
+### app.version
+
+Get the application version.
+
+- **Arguments:** None
+- **Return:** Software version
+
+Request:
+
+```bash
+curl \
+-u "demo:swB3/nSo1CB1X2F" \
+-d '{"jsonrpc": "2.0", "method": "app.version", "id": 1}' \
+https://miniflux.net/demo/jsonrpc.php
+```
+
+Response:
+
+```json
+{
+  "jsonrpc":"2.0",
+  "id":1,
+  "result": {
+    "version":"master"
+  }
+}
+```
+
 ### feed.list
 
 Get the list of subscriptions.

jsonrpc.php

@@ -10,6 +10,12 @@ $server->authentication(array(
     \Model\Config\get('username') => \Model\Config\get('api_token')
 ));
 
+// Get version
+$server->register('app.version', function () {
+
+    return array('version' => APP_VERSION);
+});
+
 // Get all feeds
 $server->register('feed.list', function () {