link to the Gitter chat room

Having a chat is desirable because real-time discussions are sometimes
much more efficient than typing up issue comments. I tested this by
walking a first-time contributor through Git and the pull request
process.

Gitter is a chat service with good GitHub integration. The chat rooms
are fairly open and can be viewed without having to log in. For
logged-in users, there is an IRC bridge.

.travis.yml

@@ -64,3 +64,11 @@ deploy:
       tags: true
       branch: master
       python: '2.7'
+
+notifications:
+  webhooks:
+    urls:
+      - https://webhooks.gitter.im/e/cda77870362da0942755
+    on_success: change
+    on_failure: always
+    on_start: never

CONTRIBUTING.rst

@@ -105,6 +105,13 @@ This can take a week.
 Please fix any issues that are discovered during this process.
 Feel free to force-push your updates to the pull request branch.
 
+If you need assistance for your pull request, you can
+
+  - chat in `our Gitter room <https://gitter.im/gcovr/gcovr>`_
+  - discuss your problem in an issue
+  - open an unfinished pull request as a work in progress (WIP),
+    and explain what you've like to get reviewed
+
 How to set up a development environment
 ---------------------------------------
 

README.rst

@@ -5,7 +5,7 @@ generate GCC code coverage reports
 
 website_ • documentation_ • bugtracker_ • `GitHub <repo_>`_
 
-|travis-ci-badge| |appveyor-ci-badge| |pypi-badge| |codecov-badge|
+|travis-ci-badge| |appveyor-ci-badge| |pypi-badge| |codecov-badge| |gitter-badge|
 
 .. begin abstract
 
@@ -60,6 +60,9 @@ Example HTML details:
 .. |codecov-badge| image:: https://codecov.io/gh/gcovr/gcovr/branch/master/graph/badge.svg
    :target: https://codecov.io/gh/gcovr/gcovr/branch/master
    :alt: Codecov status
+.. |gitter-badge| image:: https://badges.gitter.im/gcovr/gcovr.svg
+   :target: https://gitter.im/gcovr/gcovr
+   :alt: Gitter chat
 
 .. end links
 

appveyor.yml

@@ -37,3 +37,11 @@ build: off
 test_script:
   - 'python -m pytest -v --cov=gcovr --cov-branch gcovr doc/examples'
   - 'codecov -X gcov search'
+
+
+notifications:
+  - provider: Webhook
+    url: https://webhooks.gitter.im/e/5c98eaf2d3e76753369e
+    on_build_success: false
+    on_build_failure: true
+    on_build_status_changed: true

doc/source/index.rst

@@ -11,6 +11,7 @@ gcovr
 
   * Submit a ticket |rarr| `<https://github.com/gcovr/gcovr/issues>`_
   * Stack Overflow |rarr| `<http://stackoverflow.com/search?q=[gcovr]>`_
+  * Chat on Gitter |rarr| `<https://gitter.im/gcovr/gcovr>`_
 
 * Download