Added dockerfile and updated target api version to 1.1.7.

Author: nero120

dockerfile

@@ -0,0 +1,20 @@
+FROM node:10.14.2-alpine
+
+# Set environment variables
+ENV XBROWSERSYNC_API_VERSION 1.1.7
+
+WORKDIR /usr/src/api
+
+# Download release and unpack
+RUN wget -q -O release.tar.gz https://github.com/xBrowserSync/api/archive/v$XBROWSERSYNC_API_VERSION.tar.gz \
+	&& tar -C . -xzf release.tar.gz \
+	&& rm release.tar.gz \
+	&& mv api-$XBROWSERSYNC_API_VERSION/* . \
+	&& rm -rf api-$XBROWSERSYNC_API_VERSION/
+
+# Install dependencies
+RUN npm install --only=production
+
+# Expose port and start api
+EXPOSE 8080
+CMD [ "node", "dist/api.js"]