Merge pull request #2022 from kabilar/gitignore

Add text from the Handbook to the rejected user email

dandiapi/api/templates/api/mail/rejected_user_message.txt

@@ -3,11 +3,17 @@ Dear {{ greeting_name }},
 
 Your DANDI account has been denied approval.
 {% if rejection_reason %}
-    Reason:
+    Detailed reason:
     {{ rejection_reason }}
 {% endif %}
 
-If you would like to appeal this decision, please contact the DANDI admins at help@dandiarchive.org.
+DANDI is freely accessible to the neuroscience research community. Membership is usually granted automatically to GitHub accounts with a .edu or similar academic email. If your registration is denied:
+
+- With an academic email not linked to your GitHub, please contact help@dandiarchive.org for assistance using this academic email address to verify your academic affiliation.
+
+- Without an academic email, account approval is still possible under specific circumstances. You can appeal the decision by contacting help@dandiarchive.org.
+
+For more information, see the "Create a DANDI Account page" at https://www.dandiarchive.org/handbook/16_account.
 
 Sincerely,