updated documentation around container usage

README.MD

@@ -27,33 +27,10 @@ For any additional help, join our [Discord server](http://discord.jikan.moe/).
 ### 🐳 Docker Installation
 We distribute the app as a container image so you can just run it:
 ```bash
-docker run -d --name=jikan-rest -p 8080:8080 -v ./.env:/app/.env jikan-rest:latest
+docker run -d --name=jikan-rest -p 8080:8080 -v ./.env:/app/.env jikanme/jikan-rest:latest
 ```
 
-Additionally, there is a `Dockerfile` in the repo which you can use to build the container image and startup the app in a container:
-```bash
-docker build -t jikan-rest:nightly .
-docker run -d --name=jikan-rest -p 8080:8080 -v ./.env:/app/.env jikan-rest:nightly
-```
-
-#### Note for Podman
-
-If you build the container image yourself with podman, the resulting image format will be OCI by default.
-To make the health checks work in that situation you need to run the container the following way:
-```bash
-podman run -d --name=jikan-rest -p 8080:8080 -v ./.env:/app/.env --health-start-period=5s --health-cmd="curl --fail http://localhost:2114/health?plugin=http || exit 1" jikan-rest:nightly
-```
-
-#### Configuration of the docker container
-
-You can change the settings of Jikan through setting environment variables via the `-e` command line argument option for the `docker run` command.
-These environment variables are the same as the options found in the `.env` file.
-There are additional configuration options:
-
-| Name                   | Description                                                               |
-|------------------------|---------------------------------------------------------------------------|
- | RR_MAX_WORKER_MEMORY   | (Number) Configures the available memory in megabytes for the php scripts |
- | RR_MAX_REQUEST_SIZE_MB | (Number) Configures the max allowed request body size in megabytes        |
+For more information please refer to our [container usage guide](container_usage.md).
 
 ## Public REST API
 If you don't want to host your instance, there's a public API available.

container_usage.md

@@ -0,0 +1,58 @@
+# 🐳 Running Jikan API in a container
+
+```bash
+docker run -d --name=jikan-rest -p 8080:8080 -v ./.env:/app/.env jikanme/jikan-rest:latest
+```
+- Container listens on port `8080` for http requests
+- By mounting your .env file on the container via `-v ./.env:/app/.env` command line option for `docker run` you can configure Jikan API.
+
+> **Important**: You need to either mount a `.env` file on the container or specify the configuration through environment variables to make Jikan API work. Jikan API needs a MongoDB and optionally a search engine. In high load environments additionally a `redis` server is required too. The configuration should point to the correct address of these services.
+
+> **Tip**: If you run the container on a non-default network, you can use the container names in the configuration to specify the address of services like MongoDB and TypeSense/ElasticSearch. However this is not a concern if you use `docker-compose`.
+
+There is also a `Dockerfile` in the repo which you can use to build the container image and startup the app in a container:
+```bash
+docker build -t jikan-rest:nightly .
+docker run -d --name=jikan-rest -p 8080:8080 -v ./.env:/app/.env jikan-rest:nightly
+```
+
+#### Note for Podman
+
+If you build the container image yourself with podman, the resulting image format will be OCI by default.
+To make the health checks work in that situation you need to run the container the following way:
+```bash
+podman run -d --name=jikan-rest -p 8080:8080 -v ./.env:/app/.env --health-start-period=5s --health-cmd="curl --fail http://localhost:2114/health?plugin=http || exit 1" jikan-rest:nightly
+```
+
+#### Configuration of the container
+
+You can change the settings of Jikan through setting environment variables via the `-e` command line argument option for the `docker run` command.
+These environment variables are the same as the options found in the `.env` file. We also provide a sample file called `.env.dist`.      
+Additionally, you can use the `--env-file` option of `docker run` to specify configuration for Jikan, in which case you put all the configuration in the env file.
+```bash
+docker run -d --name=jikan-rest -p 8080:8080 --env-file ./env.list jikanme/jikan-rest:latest
+```
+The env-file should contain env var value pairs line by line.
+```
+VAR1=value1
+VAR2=value2
+```
+There are additional configuration options:
+
+| Name                           | Description                                                                                                               |
+|--------------------------------|---------------------------------------------------------------------------------------------------------------------------|
+| RR_MAX_WORKER_MEMORY           | (Number) Configures the available memory in megabytes for the php scripts                                                 |
+| RR_MAX_REQUEST_SIZE_MB         | (Number) Configures the max allowed request body size in megabytes                                                        |
+ | JIKAN_QUEUE_WORKER_PROCESS_NUM | (Number) Configures the number of running queue worker processes. (You want to increase this if you experience huge load) |
+
+You can read more about additional configuration options on the [Configuration Wiki page](https://github.com/jikan-me/jikan-rest/wiki/Configuration).
+
+## Some facts about the container image
+
+- Jikan uses RoadRunner as an application server within the container.
+- Both `wget` and `curl` exists in the container image.
+- Via Roadrunner multiple processes are running in the container, and their logs are aggregated and forwarded to `stdout`.
+  - These processes are:
+    - the php processes ingesting the http requests
+    - [Supercronic](https://github.com/aptible/supercronic), which runs cron jobs.
+    - Queue workers for populating the search index and other background jobs.