Add temporary debug GET mapping at /ping

.gitignore

-# IntelliJ IDEA/PyCharm project files
+# IntelliJ IDEA project files
 .idea/
 
 .vagrant/
+
+**/cockroach-data/

shortener/src/main/kotlin/xyz/upbshrt/shortener/controller/UrlShorteningController.kt

@@ -26,6 +26,11 @@ class UrlShorteningController @Autowired constructor(private val repository: Url
     private fun handleMalformedId(id: String): Nothing =
         throw ResponseStatusException(HttpStatus.BAD_REQUEST, "'$id' is not a valid id for linking to a URL.")
 
+    @GetMapping("/ping")
+    fun ping(): String {
+        return "pong";
+    }
+
     /*
      * We use a URI instead of a URL here because Java has the ability to open InputStreams from URLs using
      * URL.openStream. Because that ability exists, URLStreamHandlers are used for certain protocols and the
@@ -49,9 +54,9 @@ class UrlShorteningController @Autowired constructor(private val repository: Url
      *   a provided [id] is malformed, or a mapped URL already exists for the supplied [id].
      */
     @PostMapping("/")
-    fun shortenUrl(@RequestParam("url")      uri: URI,
+    fun shortenUrl(@RequestParam("url") uri: URI,
                    @Pattern(regexp = "[a-zA-Z0-9]+")
-                   @RequestParam(required = false) id:  String?): ResponseEntity<String> {
+                   @RequestParam(required = false) id: String?): ResponseEntity<String> {
         if (!allowedUrlProtocols.contains(uri.scheme))
             throw ResponseStatusException(
                 HttpStatus.FORBIDDEN,