ci: Integrate Zeus and release with the bot (#403)

* ci: Configure Zeus
* ci: Configure bot releases
* meta: Update contributing guidelines
* meta: Fix version bump docs

Author: jan-auer

.github/release.yml

@@ -0,0 +1,5 @@
+store: zeus
+targets:
+  - name: github
+    changelog: History.md
+  - npm

.travis.yml

@@ -1,6 +1,3 @@
-branches:
-  only:
-    - master
 sudo: false
 language: node_js
 node_js:
@@ -9,7 +6,31 @@ node_js:
   - "6"
   - "7"
   - "8"
+
 cache:
   directories:
     - node_modules
+
+branches:
+  only:
+    - master
+
 script: npm run test-full
+
+matrix:
+  include:
+    - script: npm pack
+      node_js: "8"
+      after_success:
+        - npm install -g @zeus-ci/cli
+        - zeus upload -t "application/tar+npm" *.tgz
+
+notifications:
+  webhooks:
+    urls:
+      - https://zeus.ci/hooks/b152d48c-d694-11e7-99e7-0a580a28020f/public/provider/travis/webhook
+    on_success: always
+    on_failure: always
+    on_start: always
+    on_cancel: always
+    on_error: always

CONTRIBUTING.md

@@ -1,11 +1,9 @@
 ## How to release raven-node:
-  * [ ] Run the manual memory tests in `test/manual` to make sure we didn't introduce a memory leak
-    * [ ] Consider whether any changes warrant additions to these tests
-  * [ ] Stop and think "What version number should this be according to SemVer?"
-  * [ ] Bump version number in `package.json`.
-  * [ ] Add an entry to the [History](https://github.com/getsentry/raven-node/blob/master/History.md) file.
-  * [ ] Commit new version, create a tag (`git tag -a v1.2.3 -m "Version 1.2.3"`). Push to GitHub (`git push --follow-tags`).
-  * [ ] `$ npm publish` to push to npm.
-  * [ ] Verify that `npm install raven@1.2.3` works.
-  * [ ] Copy History entry into a new GH Release: https://github.com/getsentry/raven-node/releases
-  * [ ] glhf
+
+* [ ] Run the manual memory tests in `test/manual` to make sure we didn't introduce a memory leak
+  * [ ] Consider whether any changes warrant additions to these tests
+* [ ] Stop and think "What version number should this be according to SemVer?"
+* [ ] Add an entry to the [History](https://github.com/getsentry/raven-node/blob/master/History.md) file.
+* [ ] Bump version number in `package.json` using `npm version -m [patch|minor|major] 'release: %s'`.
+* [ ] Push to GitHub (`git push origin master --follow-tags`).
+* [ ] Once CI builds pass, `sentry-probot` will publish a release on npm and GitHub.