Delete README.md

this is only to test the BASH script github-add-travis.sh OVERWRITE_MODE; when the OVERWRITE mode is set to 1 (default is 0) then the script re-creates the .travis.yml files and re-generates/encrypts the ENV vars. HOWEVER the script won't edit/adjust pom.xml, application.properties, grails-app/conf/BuildConfig.groovy files (those have to be adjusted manually)