Update README.rst

Author: ckng0221

README.rst

@@ -27,6 +27,12 @@ Installation
 
    pip install django-cognito-jwt
 
+To install from fork
+
+.. code-block:: shell
+
+   pip install git+https://github.com/ckng0221/django-cognito-jwt.git
+
 Usage
 =====
 
@@ -125,4 +131,4 @@ To use the backend functions, at the DJANGO_USER_MODEL, could define methods as
             except IntegrityError:
                 user = self.get(cognito_id=cognito_id)
 
-            return user
+            return user