Add docker-compose.yml to gitignore

The docker-compose.yml file is likely to be edited quite extensively by
admins when setting up an instance. To make it easier to do upgrades
down the line, it should be ignored by git.

Instead we should provide the existing docker-compose.yml as a sample
config and update the docs to have the user copy it over to the root
directory to edit it themselves.

.gitignore

@@ -78,3 +78,4 @@ docs/venv
 # docker stuff
 docker-db
 *.iml
+docker-compose.yml

docs/docs/installation/docker_en.md

@@ -28,6 +28,11 @@ echo "DOCKER_USER=$(id -u):$(id -g)" >> .env
 This probably won't need to be changed, it's only there to set basic environment
 variables for the docker compose file.
 
+Next, copy over the `docker-compose.yml` file to the main directory:
+```bash
+cp docker-resources/docker-compose.yml docker-compose.yml
+```
+
 ### Building the container
 
 The container provided is a thin wrapper around akkoma's dependencies, 

docs/docs/installation/migrating_to_docker_en.md

@@ -28,6 +28,11 @@ git clone https://akkoma.dev/AkkomaGang/akkoma.git -b stable
 cd akkoma
 ```
 
+Copy `docker-compose.yml` over to the root directory
+```bash
+cp docker-resources/docker-compose.yml docker-compose.yml
+```
+
 ### Back up your old database
 
 Change the database name as needed