Update Astra configuration settings (#156)

Author: disha257

README.md

@@ -83,10 +83,10 @@ To connect to a hosted Cassandra cluster that provides a secure connection bundl
   DATABASES = {
   'default': {
   'ENGINE': 'django_cassandra_engine',
-  'NAME': 'db_name',
-  'TEST_NAME': 'db_name',
-  'USER': username,
-  'PASSWORD': password,
+  'NAME': 'keyspace_name',
+  'TEST_NAME': 'table_name',
+  'USER': 'token',
+  'PASSWORD': token_value,
   'OPTIONS': {
   'connection': {
   'cloud': {