diff --git a/Docker-image.md b/Docker-image.md
index 0e3a0c3..39fbbb4 100644
--- a/Docker-image.md
+++ b/Docker-image.md
@@ -12,11 +12,27 @@ $ docker build -t="tracks" .
 
 And then run an instance of the image using the following command (but replacing the database connection information appropriately)
 
-$ docker run -p 3000:3000 -e DATABASE_NAME=tracks_dev -e DATABASE_HOST=db -e DATABASE_PORT=5432 -e DATABASE_USERNAME=tracks_dev -e DATABASE_PASSWORD=password -e DATABASE_TYPE=mysql2 --name tracks --link mariadb:db -t tracks
+$ docker run -p 3000:3000 --name tracks --link mariadb:db -t tracks
 
 If all went to plan, you should now be able to reach Tracks in http://localhost:3000 .
 
-*Note:* You can override files in the Docker image by using the --volume argument.
+### Environmental variables
+
+You can override database connection details by defining the environment variables in the run command, for example ”-e DATABASE_USERNAME=tracks_dev”.
+
+|Name              |Default  |For PostgreSQL |
+|------------------|---------|---------------|
+|DATABASE_NAME     |tracks   |               |
+|DATABASE_HOST     |db       |               |
+|DATABASE_PORT     |3306     |5432           |
+|DATABASE_USERNAME |tracks   |               |
+|DATABASE_PASSWORD |password |               |
+|DATABASE_TYPE     |mysql2   |postgresql     |
+|DATABASE_ENCODING |utf8     |unicode        |
+
+### Override files
+
+You can override files in the Docker image by using the --volume argument.
 
 |File               |Argument                                                 |Replace for production?|
 |-------------------|---------------------------------------------------------|-----------------------|