Switch from using GOV.UK Jenkins to Travis

This project isn't owned by GOV.UK Publishing anymore so it needs
to stop using Jenkins to publish changes.

Ideally I'd use a deploy key for this, but it turns out that you can't
attach the same deploy key to more than one repo. This means that we're
going to use a GitHub token attached to the govuk-ci user - this should
be moved to a different user in the future. To make that happen:

- Add the personal access token as a secure Heroku env var
- Change the Git URLs to push over HTTPS, not SSH

The gem_publisher gem expects there to be a file at `.gem/credentials`.
I've encrypted that file for Travis and added that file to the Travis
worker.

Same deal for the `npm publish` command.

It turns out you can only encrypt one file at a time which means
that we need to create a tar archive and then move things around
afterwards which is a little bit horrible.

In order to do this I made a secrets directory and added 2 files:

gem_credentials:

```
---
:rubygems_api_key: redacted
```

npmrc:

```
_auth = redacted
email = [email protected]
```

And then ran:

```
tar cvf secrets.tar secrets/npmrc secrets/gem_credentials
```

And encrypted that file.

.travis.yml

@@ -1,11 +1,27 @@
 language: ruby
 sudo: false
+env:
+  global:
+    - secure: "gxjwgl9l9ZP/1t86odZyMzWyiVBkG1oFzeL+Kb6z9Dtfu954l9RbytlenTTcnRw1KtaDBZVBs0ix3K45b8T2S6JFzLQ88Z/36DmXGIN6vxctfnVD9sqbbyOuP++RhibK+qUqbPRHo6a3wBsMQ87DMj5S6pJe3dxbCKRXa8zcMd0="
+before_install:
+  - openssl aes-256-cbc -K $encrypted_df4ab1bff570_key -iv $encrypted_df4ab1bff570_iv -in .travis/secrets.tar.enc -out .travis/secrets.tar -d
+  - tar xvf .travis/secrets.tar
+  - mkdir -p ~/.gem/
+  - mv secrets/gem_credentials ~/.gem/credentials
+  - mv secrets/npmrc ~/.npmrc
+  - git config --global user.name "Travis CI"
+  - git config --global user.email "[email protected]"
+  - rm -f Gemfile.lock
+  - git clean -fdx
 install:
-  # Ensure that Travis install is a no-op because `jenkins.sh`
-  # installs dependencies.
-  - echo "Not running Travis installation"
+  - bundle install
 script:
-  - ./jenkins.sh
+  - bundle exec rake spec integration_tests
+deploy:
+- provider: script
+  script: 'bundle exec rake build:and_release_if_updated'
+  on:
+    branch: master
 notifications:
   email:
     on_success: never

build_tools/publisher/docs_publisher.rb

@@ -6,7 +6,7 @@
 
 module Publisher
   class DocsPublisher
-    GIT_URL = "git@github.com:alphagov/govuk_template"
+    GIT_URL = "https://#{ENV['GITHUB_TOKEN']}@github.com/alphagov/govuk_template.git"
 
     def initialize(version = GovukTemplate::VERSION)
       @version = version

build_tools/publisher/ejs_publisher.rb

@@ -4,7 +4,7 @@
 
 module Publisher
   class EJSPublisher
-    GIT_URL = "git@github.com:alphagov/govuk_template_ejs"
+    GIT_URL = "https://#{ENV['GITHUB_TOKEN']}@github.com/alphagov/govuk_template_ejs.git"
 
     def initialize(version = GovukTemplate::VERSION)
       @version = version

build_tools/publisher/jinja_publisher.rb

@@ -4,7 +4,7 @@
 
 module Publisher
   class JinjaPublisher
-    GIT_URL = "git@github.com:alphagov/govuk_template_jinja"
+    GIT_URL = "https://#{ENV['GITHUB_TOKEN']}@github.com/alphagov/govuk_template_jinja.git"
 
     def initialize(version = GovukTemplate::VERSION)
       @version = version

build_tools/publisher/mustache_publisher.rb

@@ -4,7 +4,7 @@
 
 module Publisher
   class MustachePublisher
-    GIT_URL = "git@github.com:alphagov/govuk_template_mustache"
+    GIT_URL = "https://#{ENV['GITHUB_TOKEN']}@github.com/alphagov/govuk_template_mustache.git"
 
     def initialize(version = GovukTemplate::VERSION)
       @version = version

build_tools/publisher/play_publisher.rb

@@ -4,7 +4,7 @@
 
 module Publisher
   class PlayPublisher
-    GIT_URL = "git@github.com:alphagov/govuk_template_play"
+    GIT_URL = "https://#{ENV['GITHUB_TOKEN']}@github.com/alphagov/govuk_template_play.git"
 
     def initialize(version = GovukTemplate::VERSION)
       @version = version