add codecov

.travis.yml

@@ -6,4 +6,6 @@ before_install:
 install:
   - "pip install -r requirements.txt"
 script:
-  - "python -m pytest"
\ No newline at end of file
+  - "python -m pytest --cov=codecov"
+after_success:
+  - codecov
\ No newline at end of file