Add book link in the about menu

Signed-off-by: Roberto Rosario <roberto.rosario@mayan-edms.com>

mayan/apps/common/links.py

@@ -6,7 +6,7 @@ from django.utils.translation import ugettext_lazy as _
 from mayan.apps.navigation.classes import Link
 
 from .icons import (
-    icon_about, icon_current_user_locale_profile_details,
+    icon_about, icon_book, icon_current_user_locale_profile_details,
     icon_current_user_locale_profile_edit, icon_documentation,
     icon_forum, icon_license, icon_object_error_list_with_icon,
     icon_setup, icon_source_code, icon_support, icon_tools
@@ -35,6 +35,10 @@ def get_kwargs_factory(variable_name):
 link_about = Link(
     icon_class=icon_about, text=_('About this'), view='common:about_view'
 )
+link_book = Link(
+    icon_class=icon_book, tags='new_window', text=_('Get the book'),
+    url='https://mayan-edms.com/book/'
+)
 link_current_user_locale_profile_details = Link(
     icon_class=icon_current_user_locale_profile_details,
     text=_('Locale profile'),