Highlight sentences difficult to read

Please do not merge these changes, it just highlights, so hope these sentences will be rewritten.
Also I will add here more sentences when I finish reading your excellent book :wink:
PS: Thank you for this book!

## TODO

- [ ] recommendations for quick start typical projects like rails (or guide like blog in 15 minutes), and it would be nice to read how you handle dependencies, roles etc.
- [x] ohai_plugin have deprecation warnings, so book will be outdated soon
- [x] recommendations for testing, you described a lot of tools, but I am not sure if you use all of them in your projects
- [x] no steps to generate hash for user password, so people forced to use google
- [ ] my personal pain: I forced to use centos, but repos didn't provide you a lot of services like redis, which ways you find to deal with it, build from sources, or add repositories
- [x] after installation build-essential package you can build on the server all you need, but it would be nice to remove these packages after compilation, is there any way to do it? Answer: Remove by separate recipe, but in this case on each run of chef-client it will install and remove this packages :)
- [x] more things in tips and tricks :wink:
- [x] download epub version