Tests fail for pull requests from forks

[ahaselsteiner]

I'm submitting a ...

• bug report
• feature request
• code improvement request

Expected behavior

How should it work (with the bug fixed or the feature implemented)?
Tests should succeed even if a pull request is coming from a fork.
Screenshot

Actual behavior

How does it currently work (with the bug causing problems or without the feature)?
At the moment the tests fail if a pull request was created by a fork becuase then AWS_ACCESS_KEY_ID, which is an encrypted environment variable, is not set. This is due to travis security settings: https://docs.travis-ci.com/user/pull-requests/#Pull-Requests-and-Security-Restrictions
a possible solution is to check if this pull request comes from a fork by adding something like

script:
   - 'if [ "$TRAVIS_PULL_REQUEST" != "false" ]; then bash ?????set RUN_MODE='local-dev'

to .travis.yml
When RUN_MODE is set to 'local-dev' it does not use AWS, but saves the files in the local directory instead.

Screenshot

Steps to reproduce the problem (how to see the actual behavior)

1. Fork viroconweb
2. Craete a feature branch and make a change
3. File a pull request and see how the tests will fail