update promtail-examples.md

rewrite exist example, and add more examples with descriptions

docs/promtail-examples.md

@@ -1,7 +1,10 @@
 # promtail examples
 #### In this file you can see simple examples of configure promtail
 
-For work with 2 and more sources:
+* This example of config promtail based on original docker [config](https://github.com/grafana/loki/blob/master/cmd/promtail/promtail-docker-config.yaml)
+and show how work with 2 and more sources:
+
+Filename for example: my-docker-config.yaml
 ```
 server:
   http_listen_port: 9080
@@ -35,12 +38,23 @@ scrape_configs:
       __path__: /srv/log/someone_service/*.log
 
 ```
-#### Description
+##### Description
 Scrape_config section of config.yaml contents are various jobs for parsing your logs on current host
 
 `job` and `host` these are tags on which you can filter parsed logs date on Grafana later
 
-`__path__` it is path to directory where stored your logs. (*)
+`__path__` it is path to directory where stored your logs.
+
+If you run promtail and this config.yaml in Docker container, don't forget use docker volumes for mapping real directories
+with log to those folders in the container. 
 
-* - If you run promtail and this config.yaml in Docker container, you can use docker volumes for mapping real directories
-with log to those folders in the container.
+* See next example of Dockerfile, who use our modified promtail config (my-docker-config.yaml)
+1) Create folder, for example `promtail`, then new folder build and in this filder conf and place there `my-docker-config.yaml`.
+2) Create new Dockerfile in root folder `promtail`, with contents
+```
+FROM grafana/promtail:latest
+COPY build/conf /etc/promtail
+```
+3) Create your Docker image based on original Promtail image and tag it, for example `mypromtail-image`
+3) After that you can run Docker container by this command:
+`docker run -d --name promtail --network loki_network -p 9080:9080 -v /var/log:/var/log -v /srv/log/someone_service:/srv/log/someone_service mypromtail-image -config.file=/etc/promtail/my-docker-config.yaml`