Add achievements from Hackergarten May 2025 Basel

Author: anneloredev

events.json

@@ -173,7 +173,7 @@
     },
     {
          "date": "2025-05-06",
-         "title": "Hackergarten Basel June 2025",
+         "title": "Hackergarten Basel May 2025",
          "venue": "Karakun AG",
          "address": "Elisabethenanlage 25, 4051 Basel, Switzerland",
          "links": [
@@ -183,6 +183,14 @@
              }
          ],
          "achievements": [
+             {
+                "title": "Add link to instructions for building from sources in README.md",
+                "url": "https://github.com/JabRef/jabref/pull/13070"
+            },
+            {
+                "title": "Fix subdirectory in which JabRef is to be found after building from sources",
+                "url": "https://github.com/JabRef/user-documentation/pull/563"
+            }
          ]
      },
     {
@@ -195,7 +203,8 @@
                 "url": "https://www.meetup.com/hackergarten-luzern/events/mkxjbtyhchbcb/"
             }
         ],
-        "achievements": []
+        "achievements": [
+        ]
     },
     {
         "date": "2025-04-24",