create config.json for hyperopt

.travis.yml

@@ -21,8 +21,10 @@ install:
 jobs:
   include:
     - script: pytest --cov=freqtrade --cov-config=.coveragerc freqtrade/tests/
-    - script: python freqtrade/main.py hyperopt -e 5
     - script: python freqtrade/main.py backtesting
+    - script:
+      - cp config.json.example config.json
+      - python freqtrade/main.py hyperopt -e 5
 after_success:
 - flake8 freqtrade && coveralls
 notifications: