diff --git a/Gateway-config-(basic).md b/Gateway-config-(basic).md
index f0bc408..de9b35b 100644
--- a/Gateway-config-(basic).md
+++ b/Gateway-config-(basic).md
@@ -12,4 +12,28 @@ account="protocol2.myprotocol2"
 channel="protocol2channel"
 ```
 
-See [[Gateway-config-(channel-rules)]] to see how ```protocolchannel``` or ```protocol2channel``` should be defined.
\ No newline at end of file
+See [[Gateway-config-(channel-rules)]] to see how ```protocolchannel``` or ```protocol2channel``` should be defined.
+
+### Environment variables
+
+Environment variables can be used to override configuration settings, using the form:
+
+`MATTERBRIDGE_PROTOCOL_ACCOUNT_KEY`
+
+This can be useful to protect secrets when using [[docker|Deploy: Docker]]. For example, you can override this config:
+
+```
+[mattermost]
+    [mattermost.work]
+    Team="yourteam"
+    Login="yourlogin"
+    Password="yourpass"
+```
+
+by using environment variables:
+
+```
+MATTERBRIDGE_MATTERMOST_WORK_TEAM="newteam"
+MATTERBRIDGE_MATTERMOST_WORK_LOGIN="newlogin"
+MATTERBRIDGE_MATTERMOST_WORK_PASSWORD="newpassword"
+```
\ No newline at end of file