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    3. [Separate new plugin](#3-separate-new-plugin)
    4. [Core implementations](#4-core-implementations)
 2. [Development](#development)
+   1. [RYS engines](./RYS.md)
 3. [Code style](./CODE_STYLE.md)
 4. [Common errors](./COMMON_ERRORS.md)
 5. [Repositories](./REPOSITORIES.md)
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+# Redmine plugins as a engines
+We introduce new way of development plugins for Redmine (and Easy Redmine of course) which is almast same as developing standard rails gems.
+
+# Introduce
+RYS engines are separated to few gems, and source code is on github. So for full documentation what is RYS and how it works, please check our github page.
+
+   https://github.com/easysoftware/rys
+   
+# Lukas's personal workflow
+How to start develop with RYS? There are some of my recommendations...
+
+## You need Redmine of Easy Redmine first
+Because RYS is designed for developing (easy)Redmine plugins, you need download one of it.
+
+We have prepared simple generator of RYS engines
+
+> HINT: Easy Redmine from platform version 04.00 includes rys gem. The best is use our 'devel'
+
+### Generate your engine
+
+1. Add in your Redmine gem "rys"
+2. Run rails generate of RYS
+      
+       rails generate rys:plugin NAME
+
+### Move generated code to work directory
+
+All engines will have separated GIT repository. Its better to store engines outside of ER git repository.
+
+> HINT: Use `--path` with generator.
+
+### Dummy application
+
+I like rails engines, and Rails 5 engines is the best to develop with dummy application, which not contains lot of unnecessary code. In Ruby Mine I have opened only RYS, so its fast and faster :)
+
+So I take our 'devel' repository, clone as `dummy` and remove *_ALL unnecessary plugins_*.
+
+This dummy I have symlinked to `test/dummy` in RYS engine.
+
+
+### Prepare to test
+
+1. bundle install - based my experience you need run this many times :)
+1. Be sure you have configured `config/database.yml` in your dummy.
+1. rake app:db:create app:db:migrate && rake app:easyproject:install
+1. rspec
+
+## Example
+
+How I do this... (working example)
+
+1. Get Easy Redmine
+
+       git clone devel -b devel devel
+      
+2. Setup Easy Redmine (database.yml)
+
+       bundle install --without rmagick xapian
+       
+3. Generate RYS
+
+       rails g rys:plugin ruzovy_jednorozec --path ../
+        
+4. Prepare dummy
+
+       git clone devel -b devel dummy
+       cd dummy/plugins
+       rm -r * && git checkout easyproject easy_job
+       cd easyproject/easy_plugins
+       rm -r * && git checkout easy_extensions # and all plugins requried by featue
+       cd ../../../
+       vim config/database.yml
+
+5. Link dummy to RYS
+
+       cd ../ruzovy_jednorozec
+       mkdir test
+      test folder is in `.gitignore` by default
+       
+       ln -s [~/projects/ or absolute path]dummy test/dummy
+
+6. Make it together
+      
+       bundle install --without rmagick xapian
+       rake app:db:create app:db:migrate
+       rake app:easyproject:install # this work from ER 05.00
+
+7. Ready for use
+
+RYS is ready, open RubyMine and do some code ! After that run `rspec`
+
+```bash
+.*
+
+Pending: (Failures listed here are expected and do not affect your suite's status)
+
+  1) Model test Fail something
+     # No reason given
+     Failure/Error: expect(true).to eq false
+
+       expected: false
+            got: true
+
+       (compared using ==)
+     # ./spec/models/model_spec.rb:8:in `block (2 levels) in <top (required)>'
+
+Finished in 0.50731 seconds (files took 2.92 seconds to load)
+2 examples, 0 failures, 1 pending
+```
+### Conclusion
+
+When code is pushed to gitlab, CI will run test with whole devel repository (by default).
+This is guide based my experience with RYS development, it may not be for everyone ok... 
+
+#### Cons
+* Test only part of application - other plugins can change behaviour and in this way you missed it...
+* Another window with whole ER is needed. 
+
+#### Pros
+* Very fast development - test finished in few seconds, almost like in real world.
+* Based on LOC in every RYS engine, Ruby Mine work faster, consume less RAM - on my old Mac is much better.
+* TDD is now possible.