Use Let's Encrypt for SSL certificates

configuration.nix

@@ -39,6 +39,12 @@
     passwordAuthentication = false;
   };
 
+  # Let's Encrypt certificates
+  security.acme = {
+    acceptTerms = true;
+    email = "manu@beffara.org";
+  };
+
   # Nginx web server
   services.nginx = {
     enable = true;
@@ -46,8 +52,7 @@
       default = true;
       forceSSL = true;
       root = "/data/web/root";
-      sslCertificate = "/data/web/cert/beffara.org.crt";
-      sslCertificateKey = "/data/web/cert/beffara.org.key";
+      enableACME = true;
 
       locations."/owncloud/" = {
         alias = "/data/web/nextcloud/site/";