Add separate production, testserver, and demo deployments

config.mk.example

@@ -1,17 +1,33 @@
 # Copy this file to config.mk. It contains non-secret Make configuration only.
 
-# Remote SSH administrator supplied by the hoster or LXC configuration. Use
-# root, ubuntu, or another account with passwordless sudo. This is deliberately
-# not the unprivileged gardomatic service account.
+# Each deployment has its own host configuration. The SSH administrator is
+# supplied by the hoster or LXC configuration. Use root, ubuntu, or another
+# account with passwordless sudo, not the unprivileged gardomatic service account.
+
+# Production ------------------------------------------------------------------
 PRODUCTION_HOST =
 PRODUCTION_SSH_USER = root
 PRODUCTION_SSH_PORT = 22
-
-# Optional private key path on the local workstation. Leave empty to use the
-# SSH agent and normal ~/.ssh/config resolution. Paths must not contain spaces.
 PRODUCTION_SSH_IDENTITY_FILE =
-
-# Target operating system and architecture. Supported provisioning architectures
-# are amd64 and arm64.
 PRODUCTION_GOOS = linux
 PRODUCTION_GOARCH = amd64
+
+# Test server -----------------------------------------------------------------
+TESTSERVER_HOST =
+TESTSERVER_SSH_USER = root
+TESTSERVER_SSH_PORT = 22
+TESTSERVER_SSH_IDENTITY_FILE =
+TESTSERVER_GOOS = linux
+TESTSERVER_GOARCH = amd64
+
+# Public demo -----------------------------------------------------------------
+DEMO_HOST =
+DEMO_SSH_USER = root
+DEMO_SSH_PORT = 22
+DEMO_SSH_IDENTITY_FILE =
+DEMO_GOOS = linux
+DEMO_GOARCH = amd64
+
+# Identity-file paths are local and must not contain spaces. Leave them empty to
+# use the SSH agent and normal ~/.ssh/config resolution. Supported architectures
+# are amd64 and arm64; all deployment targets run Linux.