Merge pull request academicpages#2814 from librautoo/master

update readme file

Author: rjzupkoii

README.md

@@ -26,14 +26,29 @@ When you are initially working your website, it is very useful to be able to pre
     ```bash
     sudo apt install ruby-dev ruby-bundler nodejs
     ```
+    If you see error `Unable to locate package ruby-bundler`, `Unable to locate package nodejs `, run the following:
+    ```bash
+    sudo apt update && sudo apt upgrade -y
+    ```
+    then try run `sudo apt install ruby-dev ruby-bundler nodejs` again.
+
     On MacOS the commands are:
     ```bash
     brew install ruby
     brew install node
     gem install bundler
     ```
 1. Run `bundle install` to install ruby dependencies. If you get errors, delete Gemfile.lock and try again.
+
+    If you see file permission error like `Fetching bundler-2.6.3.gem ERROR:  While executing gem (Gem::FilePermissionError) You don't have write permissions for the /var/lib/gems/3.2.0 directory.` or `Bundler::PermissionError: There was an error while trying to write to /usr/local/bin.`
+    Install Gems Locally (Recommended):
+    ```bash
+    bundle config set --local path 'vendor/bundle'
+    ```
+    then try run `bundle install` again. If succeeded, you should see a folder called `vendor` and open `.gitignore` then add `vendor` inside it.
+
 1. Run `jekyll serve -l -H localhost` to generate the HTML and serve it from `localhost:4000` the local server will automatically rebuild and refresh the pages on change.
+    You may also try `bundle exec jekyll serve -l -H localhost` to ensure jekyll to use specific dependencies on your own local machine.
 
 If you are running on Linux it may be necessary to install some additional dependencies prior to being able to run locally: `sudo apt install build-essential gcc make`