Setup celery before setting up database (VNOI-Admin#2)

- Setup celery before setting up database
- Added useful notes and docker hub link to tiervnoj

Author: minhnhatnoe

docs/judge/setting_up_a_judge.md

@@ -38,6 +38,8 @@ may give you more control at the expense of more administrative complexity.
 
 ### With Docker
 
+#### Pre-built
+
 We maintain Docker images with all runtimes we support in the
 [runtimes-docker](https://github.com/DMOJ/runtimes-docker) project.
 
@@ -49,6 +51,9 @@ and tested every week to contain the latest runtime versions.
 
 ?> VNOJ uses a custom tier, `tiervnoj`, which contains all the runtimes in Tier 1
 and some additional ones. You can find the list of supported runtimes [here](https://oj.vnoi.info/runtimes).
+The Docker image is maintained at [vnoj/judge-tiervnoj](https://hub.docker.com/r/vnoj/judge-tiervnoj).
+
+#### From source
 
 The session below build a `judge-tiervnoj`:
 
@@ -62,6 +67,10 @@ The session below spawns a `tiervnoj` judge image in the same server as the site
 **It expects problems to be placed on the host under `/mnt/problems`, and judge-specific
 configuration to be in `/mnt/problems/judge.yml`.**
 
+?> For first time developers: Both the judge and site can share a common problems folder,
+which is specified at `DMOJ_PROBLEM_DATA_ROOT` in `settings.py` for the site and as below
+for the judge.
+
 Your `judge.yml` file should look something like below:
 
 ```yaml

docs/site/installation.md

@@ -4,7 +4,7 @@
 
 ```shell-session
 $ apt update
-$ apt install git gcc g++ make python3-dev python3-pip libxml2-dev libxslt1-dev zlib1g-dev gettext curl redis-server
+$ apt install git gcc g++ make python3-dev python3-pip python3-venv libxml2-dev libxslt1-dev zlib1g-dev gettext curl redis-server pkg-config
 $ curl -sL https://deb.nodesource.com/setup_18.x | sudo -E bash -
 $ apt install nodejs
 ```
@@ -61,7 +61,7 @@ Install Node.js packages:
 (vnojsite) $ npm install
 ```
 
-You will now need to configure `dmoj/local_settings.py`. You should make a copy of [this sample settings file](https://github.com/DMOJ/docs/blob/master/sample_files/local_settings.py) and read through it, making changes as necessary. Most importantly, you will want to update MariaDB credentials.
+You will now need to configure `dmoj/local_settings.py`. You should make a copy of [this sample settings file](https://github.com/VNOI-Admin/vnoj-docs/blob/master/sample_files/local_settings.py) and read through it, making changes as necessary. Most importantly, you will want to update MariaDB credentials.
 
 ?> Leave debug mode on for now; we'll disable it later after we've verified that the site works. <br> <br>
 Generally, it's recommended that you add your settings in `dmoj/local_settings.py` rather than modifying `dmoj/settings.py` directly. `settings.py` will automatically read `local_settings.py` and load it, so write your configuration there.
@@ -87,6 +87,20 @@ You will also need to generate internationalization files.
 (vnojsite) $ ./manage.py compilejsi18n
 ```
 
+## Setting up Celery
+
+The VNOJ uses Celery workers to perform most of its heavy lifting, such as batch rescoring submissions. We will use Redis as its broker, though note that other brokers that Celery supports will work as well.
+
+Start up the Redis server, which is needed by the Celery workers.
+
+```shell-session
+$ service redis-server start
+```
+
+Configure `local_settings.py` by uncommenting `CELERY_BROKER_URL` and `CELERY_RESULT_BACKEND`. By default, Redis listens on localhost port 6379, which is reflected in `local_settings.py`. You will need to update the addresses if you changed Redis's settings.
+
+We will test that Celery works soon.
+
 ## Setting up database tables
 
 We must generate the schema for the database, since it is currently empty.
@@ -112,20 +126,6 @@ You should create an admin account with which to log in initially.
 (vnojsite) $ ./manage.py createsuperuser
 ```
 
-## Setting up Celery
-
-The VNOJ uses Celery workers to perform most of its heavy lifting, such as batch rescoring submissions. We will use Redis as its broker, though note that other brokers that Celery supports will work as well.
-
-Start up the Redis server, which is needed by the Celery workers.
-
-```shell-session
-$ service redis-server start
-```
-
-Configure `local_settings.py` by uncommenting `CELERY_BROKER_URL` and `CELERY_RESULT_BACKEND`. By default, Redis listens on localhost port 6379, which is reflected in `local_settings.py`. You will need to update the addresses if you changed Redis's settings.
-
-We will test that Celery works soon.
-
 ## Running the server
 
 Now, you should verify that everything is going according to plan.