add docker support (#75)

* add docker support

* exit with gateway status on debug mode

* Remove timezone variable

* remove copying sample config

start.sh

@@ -0,0 +1,19 @@
+ #!/bin/sh
+
+if ! [ -f '/config/config.yaml' ]; then
+    echo "There is no config.yaml! An example is created."
+    cp /application/config.yaml.example /config/config.yaml.example
+    exit 1
+fi
+
+cd /application
+if [ "$DEBUG" = 'true' ]; then
+    echo "Start in debug mode"
+    python3 ./gateway.py -d
+    status=$?
+    echo "Gateway died..."
+    exit $status
+else
+    echo "Start in normal mode"
+    python3 ./gateway.py
+fi