docs: add the config file names to the README

Add the names of the config file values to the README, making it clear
how to write the config file without first modifying the config in the
GUI.

Resolves aceberg#14

README.md

@@ -34,25 +34,22 @@ Or use [docker-compose.yml](docker-compose.yml)
 ## Binary
 PPA for amd64 .deb is [here](https://github.com/aceberg/ppa). For other binary options plese look at the [latest release](https://github.com/aceberg/ExerciseDiary/releases/latest).
 
-
 ## Config
-
-
 Configuration can be done through config file or environment variables
 
-| Variable  | Description | Default |
-| --------  | ----------- | ------- |
-| AUTH | Enable Session-Cookie authentication | false |
-| AUTH_EXPIRE | Session expiration time. A number and suffix: **m, h, d** or **M**. | 7d |
-| AUTH_USER | Username | "" |
-| AUTH_PASSWORD | Encrypted password (bcrypt). [How to encrypt password with bcrypt?](docs/BCRYPT.md) | "" |
-| HOST | Listen address | 0.0.0.0 |
-| PORT   | Port for web GUI | 8851 |
-| THEME | Any theme name from https://bootswatch.com in lowcase or [additional](https://github.com/aceberg/aceberg-bootswatch-fork) (emerald, grass, sand)| grass |
-| COLOR | Background color: light or dark | light |
-| HEATCOLOR | HeatMap color | #03a70c |
-| PAGESTEP | Items on one page | 10 |
-| TZ | Set your timezone for correct time | "" |
+| Variable  | Config File | Description | Default |
+| --------  | ----------- | ----------- | ------- |
+| AUTH | auth | Enable Session-Cookie authentication | false |
+| AUTH_EXPIRE | auth_expire | Session expiration time. A number and suffix: **m, h, d** or **M**. | 7d |
+| AUTH_USER | auth_user | Username | "" |
+| AUTH_PASSWORD | auth_password | Encrypted password (bcrypt). [How to encrypt password with bcrypt?](docs/BCRYPT.md) | "" |
+| HOST | host | Listen address | 0.0.0.0 |
+| PORT   | port | Port for web GUI | 8851 |
+| THEME | theme | Any theme name from https://bootswatch.com in lowcase or [additional](https://github.com/aceberg/aceberg-bootswatch-fork) (emerald, grass, sand)| grass |
+| COLOR | color | Background color: light or dark | light |
+| HEATCOLOR | heatcolor | HeatMap color | #03a70c |
+| PAGESTEP | pagestep | Items on one page | 10 |
+| TZ | | Set your timezone for correct time | "" |
 
 ## Options