Merge pull request rails#50181 from akhilgkrishnan/add-codehighlight

Add markdown code highlight for bash script [skip ci]

Author: rafaelfranca

README.md

@@ -58,19 +58,24 @@ In addition to that, Rails also comes with:
 
 1. Install Rails at the command prompt if you haven't yet:
 
-        $ gem install rails
+	```bash
+	$ gem install rails
+	```
 
 2. At the command prompt, create a new Rails application:
 
-        $ rails new myapp
+	```bash
+	$ rails new myapp
+	```
 
    where "myapp" is the application name.
 
 3. Change directory to `myapp` and start the web server:
 
-        $ cd myapp
-        $ bin/rails server
-
+	```bash
+	$ cd myapp
+	$ bin/rails server
+	```
    Run with `--help` or `-h` for options.
 
 4. Go to `http://localhost:3000` and you'll see the Rails bootscreen with your Rails and Ruby versions.