Install error on Debian Stretch

[albrechtd]

Please excuse me if this is dumb question, as I'm absolutely not familiar with Ruby…

I tried to install the redmine tagging plug-in on a Debian Stretch box without connection to the Internet (but to local repos, and of course to the ZIP):

apt-get install ruby-acts-as-taggable-on
cd /usr/share/redmine/plugins
unzip ~/redmine_tagging-master.zip
mv redmine_tagging-master redmine_tagging
cd ..
bundle install

works as expected. The last command lists, inter alia

Using acts-as-taggable-on 4.0.0

but the next command from the instructions fails:

root@test-stretch:/usr/share/redmine# bundle exec rake acts_as_taggable_on_engine:install:migrations RAILS_ENV=production --trace
rake aborted!
Don't know how to build task 'acts_as_taggable_on_engine:install:migrations' (see --tasks)
/usr/lib/ruby/vendor_ruby/rake/task_manager.rb:62:in `[]'
/usr/lib/ruby/vendor_ruby/rake/application.rb:149:in `invoke_task'
/usr/lib/ruby/vendor_ruby/rake/application.rb:106:in `block (2 levels) in top_level'
/usr/lib/ruby/vendor_ruby/rake/application.rb:106:in `each'
/usr/lib/ruby/vendor_ruby/rake/application.rb:106:in `block in top_level'
/usr/lib/ruby/vendor_ruby/rake/application.rb:115:in `run_with_threads'
/usr/lib/ruby/vendor_ruby/rake/application.rb:100:in `top_level'
/usr/lib/ruby/vendor_ruby/rake/application.rb:78:in `block in run'
/usr/lib/ruby/vendor_ruby/rake/application.rb:176:in `standard_exception_handling'
/usr/lib/ruby/vendor_ruby/rake/application.rb:75:in `run'
/usr/bin/rake:27:in `'

Calling the command with --tasks says

root@test-stretch:/usr/share/redmine# bundle exec rake acts_as_taggable_on_engine:install:migrations RAILS_ENV=production --tasks | grep tag
rake redmine:tagging:reconfigure                 # Reconfigure for inline/separate tag editing
rake redmine_tagging:test                        # Run tests

Any idea what I missed here? From Debian, I installed redmine 3.3.1-4, redmine-pgsql 3.3.1-4, ruby-acts-as-taggable-on 4.0.0-2 and all their dependencies. Other installed plug-ins are redmine_custom_workflows, redmine_default_assign, redmine_ldap_sync, redmine_ssl_auth_cn and redmine_workflow_enhancements.

Thanks in advance for any insight!