GCS documentation (#4622)

* GCS documentation and review fixes.

docs/gateway/azure.md

@@ -0,0 +1,46 @@
+# Minio Azure Gateway [![Slack](https://slack.minio.io/slack?type=svg)](https://slack.minio.io)
+Minio Gateway adds Amazon S3 compatibility to Microsoft Azure Blob Storage.
+
+## Run Minio Gateway for Microsoft Azure Blob Storage
+### Using Docker
+```
+docker run -p 9000:9000 --name azure-s3 \
+ -e "MINIO_ACCESS_KEY=azureaccountname" \
+ -e "MINIO_SECRET_KEY=azureaccountkey" \
+ minio/minio gateway azure
+```
+
+### Using Binary
+```
+export MINIO_ACCESS_KEY=azureaccountname
+export MINIO_SECRET_KEY=azureaccountkey
+minio gateway azure
+```
+## Test using Minio Browser
+Minio Gateway comes with an embedded web based object browser. Point your web browser to http://127.0.0.1:9000 ensure your server has started successfully.
+
+![Screenshot](https://github.com/minio/minio/blob/master/docs/screenshots/minio-browser-gateway.png?raw=true)
+## Test using Minio Client `mc`
+`mc` provides a modern alternative to UNIX commands such as ls, cat, cp, mirror, diff etc. It supports filesystems and Amazon S3 compatible cloud storage services.
+
+### Configure `mc`
+```
+mc config host add myazure http://gateway-ip:9000 azureaccountname azureaccountkey
+```
+
+### List containers on Microsoft Azure
+```
+mc ls myazure
+[2017-02-22 01:50:43 PST]     0B ferenginar/
+[2017-02-26 21:43:51 PST]     0B my-container/
+[2017-02-26 22:10:11 PST]     0B test-container1/
+```
+
+### Known limitations
+[Limitations](https://github.com/minio/minio/blob/master/docs/gateway/azure-limitations.md)
+
+## Explore Further
+- [`mc` command-line interface](https://docs.minio.io/docs/minio-client-quickstart-guide)
+- [`aws` command-line interface](https://docs.minio.io/docs/aws-cli-with-minio)
+- [`minfs` filesystem interface](http://docs.minio.io/docs/minfs-quickstart-guide)
+- [`minio-go` Go SDK](https://docs.minio.io/docs/golang-client-quickstart-guide)