fixes build with database schema upgrade at installation time

.travis.yml

+sudo: false
 language: python
 python:
   - "3.2"
   - "pip install -r install/requirements.txt; echo"
   - "./bin/tg2env-patch 2 /home/travis/virtualenv/python3.2.5/lib/python3.2/site-packages"
   - "pip install coveralls"
+  - "cd tracim && gearbox migration upgrade"
   
 before_script:
   - "psql -c 'create database tracim_test;' -U postgres"