update requirements.txt

requirements.txt

-Django==1.7.4
-SQLAlchemy==0.9.8
 dj-database-url==0.3.0
 dj-database-url==0.3.0
+Django==1.8.1
 django-postgrespool==0.3.0
 django-postgrespool==0.3.0
-gunicorn==19.2.1
+gunicorn==19.3.0
 psycopg2==2.6
 psycopg2==2.6
+SQLAlchemy==1.0.4
 whitenoise==1.0.6
 whitenoise==1.0.6
-wsgiref==0.1.2