Add route for retrieve course by slug

project/urls.py

@@ -31,6 +31,7 @@ urlpatterns = [
     path('auth/', include(('apps.auth.urls', 'lilcity'))),
     path('courses/', CoursesView.as_view(), name='courses'),
     path('course/<int:pk>/', CourseView.as_view(), name='course'),
+    path('course/<str:slug>/', CourseView.as_view(), name='course'),
     path('course/<int:course_id>/like', likes, name='likes'),
     path('course/<int:course_id>/comment', coursecomment, name='coursecomment'),
     path('lesson/<int:pk>/', LessonView.as_view(), name='lesson'),