This happens because Travis does not supply the environment variables to pull requests that are coming from forks. The reason behind this is that people could expose the environment variables by printing them. (for example adding echo $HEROKU_API_KEY to the .travis.yml and submitting that as a pull request)
This happens because Travis does not supply the environment variables to pull requests that are coming from forks. The reason behind this is that people could expose the environment variables by printing them. (for example adding
echo $HEROKU_API_KEYto the .travis.yml and submitting that as a pull request)More information on the Travis docs