Use SSH for deploying

This allows access to only be granted to this repository and will
allow more fine grained control for managing the forecast data and
website output separately. It required setting up an SSH key as an
environmental variable in Travis.

.travis.yml

@@ -10,9 +10,8 @@ script:
   - Rscript PortalForecasts.R
 
 deploy:
-  provider: pages
+  provider: script
   skip_cleanup: true
-  github_token: $GITHUB_TOKEN # Set in travis-ci.org dashboard
-  local_dir: docs
+  script: deploy.sh
   on:
     branch: master

deploy.sh

@@ -0,0 +1,7 @@
+eval "$(ssh-agent -s)" # Start the ssh agent
+echo "$DEPLOY_KEY" > deploy_key.pem
+chmod 600 deploy_key.pem # This key should have push access
+ssh-add deploy_key.pem
+git add docs/index.html
+git commit -m "Automatic website update"
+git push origin master