fix(discourse): track the Ruby version Discourse requires

Discourse main now pins `ruby "~> 4.0.0"` in its Gemfile, so `bundle install`
aborts with exit 18 on containers built against the hardcoded Ruby 3.4.4. The
update path never touched Ruby at all, so every existing install breaks.

Discourse ships no .ruby-version, so read the pinned version from
Gemfile.lock's RUBY VERSION stanza and hand it to setup_ruby — on install
(repo is now cloned before the runtime setup) and on update (after the git
pull, so a bumped requirement is picked up). Also silence bundler's root
warning, split the update into separate progress steps, and skip the
unused global Rails gem.

ct/discourse.sh

@@ -51,16 +51,33 @@ function update_script() {
   cd /opt/discourse
   export PATH="$HOME/.rbenv/bin:$HOME/.rbenv/shims:$PATH"
   export COREPACK_ENABLE_DOWNLOAD_PROMPT=0
+  export BUNDLE_SILENCE_ROOT_WARNING=1
   set -a
   source /opt/discourse/.env
   set +a
   $STD git pull origin main
-  $STD bundle install
+  msg_ok "Updated Discourse"
+
+  # Discourse ships no .ruby-version, the required Ruby is pinned in Gemfile.lock
+  RUBY_TARGET=$(grep -A1 '^RUBY VERSION' /opt/discourse/Gemfile.lock | grep -oE '[0-9]+\.[0-9]+\.[0-9]+' | head -n1)
+  RUBY_VERSION="${RUBY_TARGET:-4.0.7}" RUBY_INSTALL_RAILS="false" setup_ruby
+  export PATH="$HOME/.rbenv/bin:$HOME/.rbenv/shims:$PATH"
+  hash -r
+
+  msg_info "Updating Dependencies"
+  cd /opt/discourse
+  $STD bundle install -j"$(nproc)"
   $STD pnpm install
+  msg_ok "Updated Dependencies"
+
+  msg_info "Running Database Migrations"
   $STD runuser -u postgres -- psql -d discourse -c "CREATE EXTENSION IF NOT EXISTS vector;"
   $STD bundle exec rails db:migrate
+  msg_ok "Ran Database Migrations"
+
+  msg_info "Precompiling Assets"
   $STD bundle exec rails assets:precompile
-  msg_ok "Updated Discourse"
+  msg_ok "Precompiled Assets"
 
   msg_info "Starting Services"
   systemctl start discourse discourse-sidekiq

install/discourse-install.sh

@@ -28,9 +28,15 @@ $STD apt install -y \
   redis-server
 msg_ok "Installed Dependencies"
 
+msg_info "Cloning Discourse"
+$STD git clone --depth 1 https://github.com/discourse/discourse.git /opt/discourse
+msg_ok "Cloned Discourse"
+
 PG_VERSION="17" PG_MODULES="pgvector" setup_postgresql
 NODE_VERSION="24" setup_nodejs
-RUBY_VERSION="3.4.4" setup_ruby
+# Discourse ships no .ruby-version, the required Ruby is pinned in Gemfile.lock
+RUBY_TARGET=$(grep -A1 '^RUBY VERSION' /opt/discourse/Gemfile.lock | grep -oE '[0-9]+\.[0-9]+\.[0-9]+' | head -n1)
+RUBY_VERSION="${RUBY_TARGET:-4.0.7}" RUBY_INSTALL_RAILS="false" setup_ruby
 
 msg_info "Configuring PostgreSQL for Discourse"
 DISCOURSE_DB_PASS=$(random_password 13)
@@ -42,7 +48,6 @@ msg_ok "Configured PostgreSQL for Discourse"
 
 msg_info "Configuring Discourse"
 DISCOURSE_SECRET_KEY=$(openssl rand -hex 64)
-$STD git clone --depth 1 https://github.com/discourse/discourse.git /opt/discourse
 cd /opt/discourse
 cat <<EOF >/opt/discourse/.env
 RAILS_ENV=production
@@ -77,6 +82,7 @@ export PATH="$HOME/.rbenv/bin:$HOME/.rbenv/shims:$PATH"
 eval "$(rbenv init - bash)" 2>/dev/null || true
 export RAILS_ENV=production
 export COREPACK_ENABLE_DOWNLOAD_PROMPT=0
+export BUNDLE_SILENCE_ROOT_WARNING=1
 $STD corepack enable
 $STD bundle config set --local deployment true
 $STD bundle config set --local without 'test development'