Add docker install doc (#1227)

* Add docker install doc

Signed-off-by: Xiang Dai <764524258@qq.com>

* feedback

Signed-off-by: Xiang Dai <764524258@qq.com>

docs/installation/README.md

@@ -2,4 +2,5 @@
 
 1. [Installing using Tanka (recommended)](./tanka.md)
 2. [Installing through Helm](./helm.md)
-3. [Installing locally](./local.md)
+3. [Installing through Docker or Docker Compose](./docker.md)
+4. [Installing locally](./local.md)

docs/installation/docker.md

@@ -0,0 +1,25 @@
+# Installing Loki with Docker or Docker Compose
+
+You can install Loki with Docker or Docker Compose for evaluating, testing, or developing Loki.
+For production, we recommend Tanka or Helm.
+
+## Prerequisites
+
+- [Docker](https://docs.docker.com/install)
+- [Docker Compose](https://docs.docker.com/compose/install) (optional, only needed for the Docker Compose install method)
+
+## Install with Docker
+
+```bash
+$ wget https://raw.githubusercontent.com/grafana/loki/v1.2.0/cmd/loki/loki-local-config.yaml -o loki-config.yaml
+$ docker run -v $(pwd):/mnt/config -p 3100:3100 grafana/loki:v1.2.0 -config.file=/mnt/config/loki-config.yaml
+$ wget https://raw.githubusercontent.com/grafana/loki/v1.2.0/cmd/promtail/promtail-docker-config.yaml -o promtail-config.yaml
+$ docker run -v $(pwd):/mnt/config -v /var/log:/var/log grafana/promtail:latest -config.file=/mnt/config/promtail-config.yaml
+```
+
+## Install with Docker Compose
+
+```bash
+$ wget https://raw.githubusercontent.com/grafana/loki/v1.2.0/production/docker-compose.yaml -o docker-compose.yaml
+$ docker-compose -f docker-compose.yaml up
+```