Update Docker.md for docker compose commands and building custom docker image

Update Docker.md for docker compose commands and building custom docker image

docs/Platforms/FOSS/Docker/Docker.md

@@ -1,3 +1,47 @@
+## Building custom Docker image
+
+This is only for developers. For normal users, do not add these options, just start with `docker compose up -d`
+
+This only builds `wekan-app` Docker image, where is Node.js 14.x and all Javascript code. This does not build `wekan-db` MongoDB image, that usually does not require modifications.
+
+Alpine Linux does not work properly with current Meteor 2 based WeKan. Ubuntu works, and has newest security fixes.
+
+Only amd64 currently works. Currently used Node.js 14.x segfaults at arm64 and s390x. Only Node.js 14.x is compatible with current version of Meteor 2 based WeKan. Trying to upgrade is in progress https://github.com/wekan/wekan/issues/5475
+
+Dockerfile is at https://raw.githubusercontent.com/wekan/wekan/main/Dockerfile
+
+For building custom image, and then running it, uncomment these lines,
+that are currently here, but line numbers could change, if that docker-compose.yml
+is later modified:
+
+https://github.com/wekan/wekan/blob/main/docker-compose.yml#L144-L146
+
+After your above modifications, text should look like this:
+
+```
+    #-------------------------------------------------------------------------------------
+    # ==== BUILD wekan-app DOCKER CONTAINER FROM SOURCE, if you uncomment these ====
+    # ==== and use commands: docker compose up -d --build
+    build:
+      context: .
+      dockerfile: Dockerfile
+    #-------------------------------------------------------------------------------------
+```
+
+Then modify ROOT_URL, etc settings as needed, see https://github.com/wekan/wekan/wiki/Settings
+
+Start WeKan with custom built Dockerfile with this command:
+```
+docker compose up -d --build
+```
+If you like to only build Dockerfile:
+```
+docker build .
+```
+You can also push your image to some Docker registry, like here it's done for WeKan:
+
+https://github.com/wekan/wekan/blob/main/releases/docker-push-wekan.sh
+
 ## Docker Containers
 
 - [GitHub](https://github.com/wekan/wekan/pkgs/container/wekan)
@@ -12,7 +56,7 @@ export ROOT_URL=http://SERVER-IP-ADDRESS-HERE
 ```
 Then start WeKan with:
 ```
-docker-compose up -d
+docker compose up -d
 ```
 
 SSL/TLS info at https://github.com/wekan/wekan/wiki/Settings
@@ -35,7 +79,7 @@ There is much more settings at well-documented [docker-compose.yml](https://raw.
 
 If you don't need to build Wekan, use prebuilt container with docker-compose.yml from https://github.com/wekan/wekan like this:
 ```
-docker-compose up -d
+docker compose up -d
 ```
 
 If you like to build from source, clone Wekan repo:
@@ -46,7 +90,7 @@ Then edit docker-compose.yml with [these lines uncommented](https://github.com/w
 ```
    #-------------------------------------------------------------------------------------
     # ==== BUILD wekan-app DOCKER CONTAINER FROM SOURCE, if you uncomment these ====
-    # ==== and use commands: docker-compose up -d --build
+    # ==== and use commands: docker compose up -d --build
     build:
       context: .
       dockerfile: Dockerfile
@@ -62,7 +106,7 @@ Then edit docker-compose.yml with [these lines uncommented](https://github.com/w
 ```
 Then you can build Wekan with 
 ```
-docker-compose up -d --build
+docker compose up -d --build
 ```
 
 ## Example for latest Wekan, port 2000 to Docker Wekan internal port 8080
@@ -112,7 +156,7 @@ docker rm wekan-app
 ```
 Then edit docker-compose.yml to have higher wekan-app image version tag, like `image: wekanteam/wekan:v4.12`. Then:
 ```
-docker-compose up -d
+docker compose up -d
 ```
 ### Images
 Quay: `image: quay.io/wekan/wekan:v4.07`
@@ -206,25 +250,25 @@ docker run -d --restart=always --name wekan --link "wekan-db:db" -e "MONGO_URL=m
 - No build step and pull from [quay](https://quay.io/repository/wekan/wekan?tab=tags)
 
 ```
-sudo docker-compose up -d --nobuild
+sudo docker compose up -d --nobuild
 ```
 
 - Build default
 ```
-sudo docker-compose up -d --build
+sudo docker compose up -d --build
 ```
 
 - Build with newer Node version:
 ```
 echo 'NODE_VERSION=v8.11.1' >> .env && \
-sudo docker-compose up -d --build
+sudo docker compose up -d --build
 ```
 
 - Build custom image off a release candidate or beta for meteor
 ```
 echo 'METEOR_EDGE=1.5-beta.17' >> .env && \
 echo 'USE_EDGE=true' >> .env && \
-sudo docker-compose up -d --build
+sudo docker compose up -d --build
 ```
 
 ## Docker env for Wekan dev
@@ -239,4 +283,4 @@ sudo docker-compose up -d --build
 
 * [Caddy Webserver Config](Caddy-Webserver-Config)
 * [Nginx Webserver Config](Nginx-Webserver-Config)
-* [Apache Webserver Config](Apache)
+* [Apache Webserver Config](Apache)