docs: update README.md

Author: yanglbme

README.md

@@ -2,13 +2,15 @@
 Hello, everyone! Welcome to the [Doocs](https://github.com/doocs) Open Source organization. The name is originated from ‘Docs’, which mainly shares various development-related knowledge in the form of documents.
 
 ## Projects
-Doocs now has the following five projects:
+Doocs now has the following seven projects excluding [intro](https://github.com/doocs/intro):
 
 - [advanced-java](https://github.com/doocs/advanced-java): A learning roadmap of advanced knowledge for Java developers.
+- [technical-books](https://github.com/doocs/technical-books): Awesome programming books list.
 - [leetcode](https://github.com/doocs/leetcode): LeetCode solutions in any programming language.
 - [coding-interview](https://github.com/doocs/coding-interview): A collection of interview questions for programmers. The main contents include ‘Coding Interviews: Questions, Analysis and Solutions’, ‘Beauty of Programming’, etc.
 - [jvm](https://github.com/doocs/jvm): A summary of the underlying principles of Java Virtual Machine.
 - [spider](https://github.com/doocs/spider): A record of crawler-related knowledge points.
+- [linux-shell](https://github.com/doocs/linux-shell): Topic about linux and shell.
 
 ## How to join
 “ *If you want to go fast, go alone. If you want to go far, go together.* ”
@@ -18,7 +20,7 @@ I believe many of you have a deep understanding that participating in open sourc
 - Communicate directly on the [issues](https://github.com/doocs/intro/issues) of this project.
 - Send an email to [contact@yanglibin.info](mailto:contact@yanglibin.info) and attach your GitHub ID, such as [yanglbme](https://github.com/yanglbme).
 
-After joining us, you can set visibility [here](https://github.com/orgs/doocs/people). We also recommend setting it to Public.
+By default, your Doocs membership will be hidden from view aftering joining us. If you'd like to display the organization icon in your profile, you can switch from "Private" to "Public" here: https://github.com/orgs/doocs/people. We also recommend setting it to Public.
 
 **Note**: At the beginning, you will not have direct 'write' permission for the project at this time, because we are not sure that your submission meets the project specifications.