add: contributing page to intro

Author: nap84

docs/00_intro/30_contribute.mdx

@@ -0,0 +1,19 @@
+---
+title: "Contributing"
+slug: "/contributing"
+---
+# Contributing
+
+The NFDI4Chem Knowledge Base is a community effort and we welcome your contributions.
+
+## Github
+
+This Knowledge Base is maintained on [GitHub](https://github.com/NFDI4Chem/knowledge_base). You can contribute directly via GitHub by following [these instructions](https://github.com/NFDI4Chem/knowledge_base/blob/contribute-page/readme/getting_started.md).
+
+## Other Contribution Options
+
+If you prefer and alternative to contributing via GitHub, no worries. Please contact [helpdesk@nfdi4chem.de](mailto:helpdesk@nfdi4chem.de). The Helpdesk can assist you in ensuring your content is included.
+
+## Questions
+
+Please contact [helpdesk@nfdi4chem.de](mailto:helpdesk@nfdi4chem.de) with any questions or if you have problems in the contributing process.