Documentation: Add mention to DEFAULT_FROM_EMAIL

Add mention and example of this new settings option
that is now available.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

docs/chapters/password_reset.rst

@@ -15,6 +15,7 @@ via the :ref:`configuration file <configuration_file>`.
 
 Example::
 
+    DEFAULT_FROM_EMAIL: '<your administrator email>'
     EMAIL_BACKEND: django.core.mail.backends.smtp.EmailBackend
     EMAIL_HOST: '<your smtp ip address or hostname>'
     EMAIL_HOST_PASSWORD: '<your smtp password>'

docs/chapters/settings.rst

@@ -37,6 +37,7 @@ http://yaml.org/). Here is an example of what the looks like::
 
     DOCUMENT_PARSING_AUTO_PARSING: true
     DOCUMENT_PARSING_PDFTOTEXT_PATH: /usr/bin/pdftotext
+    DEFAUL_FROM_EMAIL: mayan.admin@example.com
     EMAIL_BACKEND: django.core.mail.backends.smtp.EmailBackend
     EMAIL_HOST: localhost
     EMAIL_HOST_PASSWORD: ''