presigned: Fix a bug in presigned request verification.

Additionally add Docker proxy configuration.

Docker.md

@@ -9,7 +9,7 @@ sudo apt-get install Docker.io
 ### Generating `minio configs` for the first time.
 
 ```bash
-docker run -p 9000:9001 minio/minio:latest
+docker run -p 9000 minio/minio:latest
 ```
 
 ### Persist `minio configs`.
@@ -28,5 +28,26 @@ docker create -v /export --name minio-export minio/my-minio /bin/true
 You can then use the `--volumes-from` flag to mount the `/export` volume in another container.
 
 ```bash
-docker run -p 9000:9001 --volumes-from minio-export --name minio1 minio/my-minio
+docker run -p 9000 --volumes-from minio-export --name minio1 minio/my-minio
+```
+
+### Setup a sample proxy in front using Caddy.
+
+Please download [Caddy Server](https://caddyserver.com/download)
+
+Create a caddy configuration file as below, change the ip addresses for your environment.
+```bash
+cat Caddyfile
+10.0.0.3:2015 {
+    proxy / localhost:9000 {
+        proxy_header Host {host}
+    }
+    tls off
+}
+```
+
+```bash
+$ ./caddy
+Activating privacy features... done.
+10.0.0.3:2015
 ```