improve(docker): use nginx image (#4796)

The nginx image contains a newer viersion on nginx

Dockerfile

-FROM alpine:3.8
+FROM nginx:1.15-alpine
 
 LABEL maintainer="fehguy"
 
@@ -16,9 +16,6 @@ ENV SWAGGER_JSON "/app/swagger.json"
 ENV PORT 8080
 ENV BASE_URL ""
 
-RUN apk add --no-cache nginx
-RUN mkdir -p /run/nginx
-
 COPY nginx.conf /etc/nginx/
 
 # copy swagger files to the `/js` folder