Adding instructions to generate Django secret key

Author: bcopy

en/django_start_project/README.md

@@ -120,11 +120,20 @@ ALLOWED_HOSTS = ['127.0.0.1', '.pythonanywhere.com']
 
 > If you are hosting your project on `Glitch.com`, let us protect the Django secret key that needs to 
 > remain confidential (otherwise, anyone remixing your project could see it) :
->   * Create a file ```.env``` at the root of your project and add the following property in it :
+>   * First, we are going to create a random secret key. Open the Glitch terminal again, and type the following command :
 >     {% filename %}.env{% endfilename %}
 >     ```bash
->     # Remember to change the value below to any, very long, very random sequence of characters
->     SECRET='a-completely-random-string-of-letters-numbers-and-special-characters-anything-goes'
+>     python -c 'from django.core.management.utils import get_random_secret_key; \
+>           print(get_random_secret_key())'
+>     ```
+>     This should display a long random string, perfect to use a secret key for your brand new Django web site.
+>     We will now paste this key into a `.env` file that Glitch will only show you if you are the owner of the web site.    
+>   
+>   * Create a file `.env` at the root of your project and add the following property in it :
+>     {% filename %}.env{% endfilename %}
+>     ```bash
+>     # Here, inside the single quotes, you can cut and paste the random key generated above
+>     SECRET='3!0k#7ds5mp^-x$lqs2%le6v97h#@xopab&oj5y7d=hxe511jl'
 >     ```
 >   * Then update the Django settings file to inject this secret value and set the Django web site name :
 >     {% filename %}mysite/settings.py{% endfilename %}