Add PHP server file

Signed-off-by: Will Beason <willbeason@gmail.com>

index.php

@@ -0,0 +1,24 @@
+<?php
+
+// Launch this server with:
+// php -S localhost:8000 -q -c php.ini
+
+// Call the server with:
+// curl -X POST -H "Content-Type: application/json" \
+//   -d '{"arg1": "aa", "arg2": "aba"}' \
+//   http://localhost:8000
+
+// Get the raw POST data
+$rawData = file_get_contents('php://input');
+
+// Decode the JSON data
+$data = json_decode($rawData, true);
+
+$previous = '';
+$result = [];
+foreach ($data as $i => $value) {
+    $result[] = wikidiff2_inline_json_diff($previous, $value, 0);
+    $previous = $value;
+}
+
+echo json_encode($result);