Add clarifying comment about /etc/gitea write permissions

roles/gitea/tasks/install.yml

@@ -82,6 +82,11 @@
 
 # Configure Gitea
 
+# For security reasons, the Gitea developers recommend removing group write
+# permissions from /etc/gitea/ and /etc/gitea/app.ini after the first run of 
+# Gitea. User gitea needs write permissions during the first run but not 
+# subsequent runs.
+
 - name: Create Gitea config directory
   file:
     path: /etc/gitea