Test task to create web server without ANY additional libraries

Simple api service parses USD/RUR EUR/RUR exchange rates from 'http://cbr.ru' and returns as a json string. By default, local address is "/0.0.0.0:8080/"

Deploy in Docker:

• Build docker image docker build -t simple_api .

• Run server docker run -e ENV=RUN -itd -p 8080:8080 simple_api Service will be available at "/0.0.0.0:8080/"

• Run tests docker run -e ENV=TEST -t simple_api