diff --git a/docs/Software Development/06-Environment Variables.md b/docs/Software Development/06-Environment Variables.md
index 1982d79..34929e0 100644
--- a/docs/Software Development/06-Environment Variables.md	
+++ b/docs/Software Development/06-Environment Variables.md	
@@ -23,6 +23,7 @@ The following table lists the environment variables that are common to all DIT m
 | S3\_\_UPLOADS_API_BUCKET      | The name of the S3 bucket used for storing uploaded files via Uploads API |
 | SIDEKIQ\_\_USERNAME           | The username for accessing the Sidekiq web interface                      |
 | SIDEKIQ\_\_PASSWORD           | The password for accessing the Sidekiq web interface                      |
+| REDIS\_\_URL                  | The URL format for the connection string of redis database server         |
 | REDIS\_\_CONNECTION_STRING    | The connection string of redis database server                            |
 | REDIS_SENTINEL\_\_HOST        | The host name or IP address of the Redis Sentinel server                  |
 | REDIS_SENTINEL\_\_PORT        | The port number of the Redis Sentinel server                              |