fixup! Add Valkey and PostgreSQL (closes #9)

Model: deepseek-v4-pro

build.sh

@@ -35,6 +35,12 @@ apt-get -y install --no-install-recommends \
     valkey-server valkey-tools postgresql \
     nginx
 
+# Link the PostgreSQL server binaries onto PATH. They live under a versioned
+# directory (/usr/lib/postgresql/*/bin); the client psql is already on PATH.
+for p in postgres initdb pg_ctl; do
+    ln -s /usr/lib/postgresql/*/bin/"$p" /usr/local/bin/"$p"
+done
+
 # --- Go (latest) -------------------------------------------------------------
 gover="$(curl -fsSL 'https://go.dev/VERSION?m=text' | head -n1)"
 curl -fsSL "https://go.dev/dl/${gover}.linux-${arch}.tar.gz" | tar -C /usr/local -xz
@@ -131,6 +137,10 @@ rm -rf /usr/share/doc /usr/share/man /usr/share/info /usr/share/lintian
 find /usr/share/locale -mindepth 1 -maxdepth 1 ! -name 'en*' ! -name 'locale.alias' -exec rm -rf {} +
 rm -rf /root/.cache /root/.npm /root/.config /root/go /tmp/* /var/tmp/*
 
+# Valkey opens its log file at startup; recreate the log directory the
+# cleanup above removed, with its package owner.
+install -d -o valkey -g adm -m 2750 /var/log/valkey
+
 # --- sanity ------------------------------------------------------------------
 go version
 govulncheck -version
@@ -147,7 +157,11 @@ ruby --version
 bundle --version
 valkey-server --version
 valkey-cli --version
+valkey-server /etc/valkey/valkey.conf
+valkey-cli ping
+valkey-cli shutdown nosave
 psql --version
+postgres --version
 nginx -v
 hugo version
 node --version