Merge pull request #218 from RRosio/docs_update_link

Update security concerns link

Author: echarles

docs/source/public_server.rst

@@ -34,7 +34,7 @@ For general documentation on Jupyter Server, please visit the section on
     To use JupyterHub, you need a Unix server (typically Linux) running
     somewhere that is accessible to your users on a network. This may run over
     the public internet, but doing so introduces additional
-    `security concerns <https://jupyterhub.readthedocs.io/en/latest/getting-started/security-basics.html>`_.
+    `security concerns <https://jupyterhub.readthedocs.io/en/latest/tutorial/getting-started/security-basics.html>`_.