Append gem 'erb' to Gemfile as suggested by peippo

PKGBUILD

@@ -42,6 +42,7 @@ prepare() {
   cd mastodon-$pkgver
 
   echo "gem 'psych', '< 4'" >> Gemfile
+  echo "gem 'erb'" >> Gemfile
 }
 
 build() {

mastodon.install

@@ -16,8 +16,6 @@ post_upgrade() {
 
   echo "Setting ownership of mastodon files"
   find -path ./public/system -prune -o -exec chown -h mastodon:mastodon {} +
-  echo "Refreshing bundle"
-  sudo -u mastodon RAILS_ENV=production NODE_OPTIONS=--openssl-legacy-provider bundle install --redownload --standalone
   echo "Upgrading database schema"
   sudo -u mastodon RAILS_ENV=production bundle exec rails db:migrate
   echo "Precompiling assets"