Install required PIP packages

.travis.yml

@@ -17,6 +17,8 @@ before_install:
     - sudo apt-get update
     - sudo apt-get install gettext
     - pip3 install invoke
+    - pip3 install mysqlclient
+    - pip3 install psycopg2
     - invoke install
     - invoke migrate
     - cd InvenTree && python3 manage.py createsuperuser --username InvenTreeAdmin --email admin@inventree.com --noinput && cd ..