updated links and contact info

Author: learnbyexample

README.md

@@ -31,18 +31,16 @@ Introduction to Linux commands and Shell scripting
 ## <a name="contributing"></a>Contributing
 
 * Please open an issue for typos/bugs/suggestions/etc
-    * Even for pull requests, open an issue for discussion before submitting PRs
-    * or [gitter group chat](https://gitter.im/learnbyexample/scripting_course) for discussion as well as for help/mentorship
+    * **Please open an issue for discussion before submitting PRs**
 * Share the repo with friends/colleagues, on social media, etc to help reach other learners
-* In case you need to reach me, use [gitter private chat](https://gitter.im/learnbyexample)
-    * or mail me at `echo 'bGVhcm5ieWV4YW1wbGUubmV0QGdtYWlsLmNvbQo=' | base64 --decode`
+* In case you need to reach me, mail me at `echo 'bGVhcm5ieWV4YW1wbGUubmV0QGdtYWlsLmNvbQo=' | base64 --decode` or send a DM via [twitter](https://twitter.com/learn_byexample)
 
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 # <a name="ebook"></a>ebook
 
 * Read as ebook on [gitbook](https://learnbyexample.gitbooks.io/linux-command-line/content/index.html)
-* Download ebook for offline reading - [link](https://www.gitbook.com/book/learnbyexample/linux-command-line/details)
+* All `legacy.gitbook.com` links are now automatically redirected to `gitbook.com`, so there's no longer an option to download ebooks for offline reading
 
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