Improve docs

README.md

@@ -1,23 +1,79 @@
 # Database Backup
 
-> A simple script to backup multiple hosts at once.
+> A simple script to backup databases from multiple hosts at once.
+
+This script backups in a configurable schedule all databases on multiple available hosts.
+It was built to run in docker and have a clean way to backup database containers.
 
 ## Usage
 
-// TODO
+1. Create a configuration file with all hosts and credentials you want to backup
+2. Point the script to it (See environment variables below). By default, it searches in the default directory for a file called `backup_hosts.json`.
+
+## Configuration
+
+A configuration file with all defaults looks like this:
+
+```json
+[
+   {
+      "host":"localhost",
+      "user":"root",
+      "password":"",
+      "port": 3306
+   }
+]
+```
+
+You can omit any field to you use the default value.
+
+For example, a configuration which backups a db on `localhost` with the `root` user and `password` `1234` on the default port `3306` would look like this:
+
+```json
+[
+   {
+      "password":"1234",
+   }
+]
+```
 
 ## Usage with docker
 
-// TODO --> Cron + Max backups
+A docker image with the script is available, to integrate nicely with existing docker infrastructure.
+
+**Note:** You need to make sure that all database containers can be reached by the script over network.
+The easiest way to achieve this is to create an external network and put the backup container and the database container in it.
+
+### Docker Compose Example
+
+This will mount the config from the `config` and `backup` folders in the same directory.
+
+```yaml
+version: '2'
+services:
+  backup:
+    image: kolaente/database-backup
+    restart: unless-stopped
+    environment:
+      CRON_TIME: 0 */3 * * *
+      DB_BACKUP_MAX: '36'
+    volumes:
+      - ./config:/config
+      - ./backups:/backups
+      - /etc/localtime:/etc/localtime:ro
+    networks:
+      - default
+      - backup
+
+networks:
+  backup:
+    external: true
+```
 
 #### Environment variables
 
-* `CRON_TIME`
-* `DB_BACKUP_MAX`
-* `DB_BACKUP_HOSTS_FILE`
-* `DB_BACKUP_FOLDER`
+* `CRON_TIME`: A cron formatted string about how often the script should run
+* `DB_BACKUP_MAX`: How many old backups to keep before cleanup
+* `DB_BACKUP_HOSTS_FILE`: Where the backup configuration file is stored
+* `DB_BACKUP_FOLDER`: Where backups should be stored
 
-### TODO
-
-* Add example on how to use it -> example `backup_hosts.json`, with explanation of defaults
-* Dockerimage