Update CONTRIBUTING.md 🔥

.gitignore

@@ -1,4 +1,5 @@
 bin/
+book/
 todo.md
 gh-md-toc
 

CONTRIBUTING.md

@@ -1,24 +1,22 @@
 # Contributing
 
 First of all, thank you for reading here to contribute! I really appriciate that. <br />
-Please do not modify files in the `book` directory as they are generated by `mdbook`. Make changes in the `src` directory instead.
 
 ## Share experience
-If you want to share your interview experience, If the company exist in the `src`, just create a `md` file with company name in the `src`. If the company is not exist, create a directory with company name and put each experience on it.
-Then for compile, you need to add your `md` file to `SUMMARY.md`.
+If you want to share your interview experience, create a directory with company name (if not exist) and put your `md` file in it.
+Then for compile, you need to add your `md` file path to `SUMMARY.md`.
 Just like this:
 ```
 src/snapp
 ├── snapp_cab_1.md
-├── snapp_cab_2.md
-├── snapp_market_pro.md
-└── snapp.md
+└── snapp_cab_2.md
 ```
 You can add your name (if you like) after the company name like: `snapp_moein.md` and that's good to write it in the file otherwise, write `unknown`.
 
 ## Install
 You need to install mdbook. Just install binaries if you are not familiar with `rust` and `cargo`. <br />
-Watch this [link](https://github.com/rust-lang/mdBook/releases) for releases.
+Watch this [link](https://github.com/rust-lang/mdBook/releases) for releases. <br />
+For mermaid charts, install [this](https://github.com/badboy/mdbook-mermaid).
 
 ## Build
 For building after your changes in the root dir of project: