Updated Github pages deployment.

Signed-off-by: Sebastian Haas <sebastian@haas.tech>

.travis.yml

@@ -20,8 +20,8 @@ after_deploy:
 - eval "$(ssh-agent -s)"
 - chmod 600 bin/gh_pages_deploy_key
 - ssh-add bin/gh_pages_deploy_key
-- git config user.email "travis@opensheetmusicdisplay.org"
-- git config user.name "travis"
+- git config --global user.email "travis@opensheetmusicdisplay.org"
+- git config --global user.name "travis"
 - chmod +x ./bin/publish_gh_page.sh
 - ./bin/publish_gh_page.sh
 before_install: