Readd travis config.

.travis.yml

@@ -1,41 +1,12 @@
-language: python
-sudo: false
-cache: pip
+sudo: required
+language: generic
 
-python:
-  - 2.7
-  - 3.3
-  - 3.4
-  - 3.5
-  - 3.5-dev
-  - 3.6
-  - 3.6-dev
-  - 3.7-dev
-  - pypy3.3-5.2-alpha1
-
-env:
-  - PYTHONHASHSEED=random
-    TEST_REQUIRE="gevent greenlet geventhttpclient fastimport"
-
-matrix:
-  include:
-    - python: pypy
-      env: TEST_REQUIRE=fastimport
-
-install:
-  - travis_retry pip install -U pip coverage codecov flake8 $TEST_REQUIRE
+services:
+  - docker
 
 script:
-  # Test without c extensions
-  - python -m coverage run -p --source=dulwich -m unittest dulwich.tests.test_suite
-
-  # Test with c extensions
-  - python setup.py build_ext -i
-  - python -m coverage run -p --source=dulwich -m unittest dulwich.tests.test_suite
-
-  # Style
-  - make style
+  - wget -O- http://travis.debian.net/script.sh | sh -
 
-after_success:
-  - python -m coverage combine
-  - codecov
+branches:
+  except:
+    - /^debian\/\d/