Try to maintain history

ci.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 set -euo pipefail
 IFS=$'\n\t'
-
+BRANCH="gh-pages"
 # Run the scan
 
 cd website
@@ -9,13 +9,14 @@ bundle install
 bundle show
 bundle exec jekyll build --verbose --destination _site
 
-if ([ $TRAVIS_BRANCH == "master" ] && [ $TRAVIS_PULL_REQUEST == "false" ]); then
-  cd _site
-  git init
-  git remote add origin "$GIT_REMOTE"
+git clone "$GIT_REMOTE" --branch "$BRANCH" /tmp/remote_site
+
+if ([ $TRAVIS_BRANCH == "keep-history" ] && [ $TRAVIS_PULL_REQUEST == "false" ]); then
+  cp -r _site/* /tmp/remote_site
+  cd /tmp/remote_site
   git add .
-  git commit -m "Deploy to GitHub Pages"
-  git push --force --quiet origin master:gh-pages > /dev/null 2>&1
+  git commit -m "Update: `date`"
+  git push --force --quiet origin > /dev/null 2>&1
   echo 'Build successful, deployed to gh-pages.'
 else
   echo "Build successful, but not deploying!"