Attempt to deploy site

@chris has setup a server[1] and added the public half of a key pair
generated using `ssh-keygen -o -t rsa -b 4096` as per the instructions
on docs.gitlab.com[2].

The `before_script` was taken from the same instructions. I set the
two variables SSH_PRIVATE_KEY and SSH_KNOWN_HOSTS in the CI/CD
settings[3].

To see if this works I'm calling `rsync` in the `script` section of
the deploy stage, using the dry-run option, `-n`.

[1] https://git.coop/cotech/website/issues/4#note_9890
[2] https://docs.gitlab.com/ee/ci/ssh_keys/#ssh-keys-when-using-the-docker-executor
[3] https://git.coop/cotech/website/settings/ci_cd

.gitlab-ci.yml

@@ -5,6 +5,13 @@ variables:
   LC_ALL: C.UTF-8
 
 before_script:
+  - 'which ssh-agent || ( apt-get update -y && apt-get install openssh-client -y )'
+  - eval $(ssh-agent -s)
+  - echo "$SSH_PRIVATE_KEY" | tr -d '\r' | ssh-add - > /dev/null
+  - mkdir -p ~/.ssh
+  - chmod 700 ~/.ssh
+  - echo "$SSH_KNOWN_HOSTS" > ~/.ssh/known_hosts
+  - chmod 644 ~/.ssh/known_hosts
   - bundle install
 
 test:
@@ -21,6 +28,7 @@ pages:
   stage: deploy
   script:
   - bundle exec jekyll build -d public
+  - rsync -anv public/ cotech@webarch2.co.uk:~/sites/default/
   artifacts:
     paths:
     - public