Merge branch 'develop' of github.com:tracim/tracim_v2 into develop

.travis.yml

@@ -23,6 +23,7 @@ matrix:
         - cd backend
       install:
         - pip install --upgrade pip setuptools
+        - pip install -e .
         - pip install -e ".[testing]"
         - pip install pytest-cov
         - pip install python-coveralls