Move all samples to the root dir

Signed-off-by: Anca Iordache <anca.iordache@docker.com>

nginx-flask-mysql/proxy/Dockerfile

@@ -0,0 +1,2 @@
+FROM nginx:1.13-alpine
+COPY conf /etc/nginx/conf.d/default.conf

nginx-flask-mysql/proxy/conf

@@ -0,0 +1,8 @@
+server {
+    listen       80;
+    server_name  localhost;
+    location / {
+        proxy_pass   http://backend:5000;
+    }
+
+}