Configure Travis CI conditional builds

and add placeholder deployment. This commit should deploy to

* `production` if on branch master AND tagged
* `staging` if on branch master
* `custom` if tagged

The custom deployment is inspired by https://zeit.co/now and should
deploy features for demonstration purposes before merging into master.

It will happen that we trigger multiple deployments with this workflow:
If we deploy to production, that is going to deploy to a custom
environment and to staging. But I think this is not too problematic.

What do you think @appinteractive @mcwimpy?

.travis.yml

@@ -33,3 +33,19 @@ after_failure:
   - wget https://raw.githubusercontent.com/DiscordHooks/travis-ci-discord-webhook/master/send.sh
   - chmod +x send.sh
   - ./send.sh failure $WEBHOOK_URL
+
+deploy:
+  - provider: script
+    script: scripts/deploy.sh nitro.human-connection.org
+    on:
+      branch: master
+      tag: true
+  - provider: script
+    script: scripts/deploy.sh nitro-staging.human-connection.org
+    on:
+      branch: master
+  - provider: script
+    script: scripts/deploy.sh "nitro-$(git rev-parse --short HEAD).human-connection.org"
+    on:
+      tag: true
+      all_branches: true

scripts/deploy.sh

@@ -0,0 +1,4 @@
+#!/bin/bash
+
+echo "See me deployed at $1 :)"
+