(ci/test): add CodeCov test coverage reporting

- add after_script to upload coverage report
- add XML output pytest.ini as CodeCov requires it
  - gitignore XML output

(docs): add dat slick coverage badge to README

Author: agilgur5

.gitignore

@@ -7,6 +7,7 @@ poetry.lock
 .pytest_cache/
 .coverage
 htmlcov/
+coverage.xml
 
 # Created by https://www.gitignore.io/api/python
 

.travis.yml

@@ -5,3 +5,5 @@ before_install: pip install poetry
 install: poetry install
 
 script: poetry run pytest tests/test_project/
+# upload coverage reports to CodeCov
+after_script: bash <(curl -s https://codecov.io/bash)

README.md

@@ -9,6 +9,7 @@
 [![dw](https://img.shields.io/pypi/dw/django-serializable-model.svg)](https://pypi.org/project/django-serializable-model/)
 <br><!-- status / activity -->
 [![build status](https://img.shields.io/travis/agilgur5/django-serializable-model/master.svg)](https://travis-ci.org/agilgur5/django-serializable-model)
+[![code coverage](https://img.shields.io/codecov/c/gh/agilgur5/django-serializable-model/master.svg)](https://codecov.io/gh/agilgur5/django-serializable-model)
 <br>
 Django classes to make your models, managers, and querysets serializable, with built-in support for related objects in ~100 LoC (shorter than this README!)
 

tests/test_project/pytest.ini

@@ -5,3 +5,4 @@ addopts = --cov django_serializable_model
   --cov-branch
   --cov-report term-missing
   --cov-report html
+  --cov-report xml