fix image in docs

README.md

@@ -48,7 +48,7 @@
 2. [Technical Meeting 2 - Jupyter Notebook](https://github.com/intsystems/discrete-variables-relaxation/blob/main/basic/basic_code.ipynb)
 3. [Technical Meeting 3 - Jupyter Notebook](https://github.com/intsystems/discrete-variables-relaxation/blob/main/demo/vizualization.ipynb)
 4. [Blog Post](https://github.com/intsystems/discrete-variables-relaxation/blob/main/assets/blog-post.pdf)
-5. [Documentation](https://intsystems.github.io/discrete-variables-relaxation/train.html)
+5. [Documentation](https://intsystems.github.io/discrete-variables-relaxation/)
 6. [Tests](https://github.com/intsystems/discrete-variables-relaxation/tree/main/tests)
 
 ## 💡 Motivation