Correct API docs path and fix pytest invocation

The earlier location http://127.0.0.1:8000/api/docs was a 404. As the
urls.py suggests, the README now reflects http://127.0.0.1:8000/api/schema/swagger-ui/

After the first install, activating the venv is done prior to installing
pytest, thus the system default pytest is being called. It is either
required to reactive venv or run pytest via python -m.

Signed-off-by: Hritik Vijay <hritikxx8@gmail.com>
Signed-off-by: Pushpit <pushpit07@gmail.com>

README.rst

@@ -206,7 +206,7 @@ Run Tests
 Use these commands to run code style checks and the test suite::
 
     black -l 100 --check .
-    DJANGO_DEV=1 pytest
+    DJANGO_DEV=1 python -m pytest
 
 
 Data import
@@ -245,7 +245,7 @@ Start the webserver::
 
 For full documentation about API endpoints use this URL::
 
-    http://127.0.0.1:8000/api/docs
+    http://127.0.0.1:8000/api/schema/swagger-ui/