Switch project to using MySQL in dev instead of SQLLite

[jonespm]

Will need to switch the Docker Compose and the Django settings.

Example where we are doing this: https://github.com/tl-its-umich-edu/my-learning-analytics/blob/master/docker-compose.yml

[ssciolla]

So here would be the steps for making this happen (in a bit more detail), based on the current status of the project:

1) Add a mysql service to docker-compose.

• This is a standard pattern we use in our projects. MyLA example above is good, but also you can look at these:
  • Placement Exams (Python/Django, but no frontend): https://github.com/tl-its-umich-edu/placement-exams/blob/803fd0b41eecdc7034c0308fc420c813563ddb7e/docker-compose.yml#L4-L21
  • Canvas Course Manager (NodeJS/Express/NestJS, but uses the same MySQL patterns): https://github.com/tl-its-umich-edu/canvas-course-manager-next/blob/c39ecc85a96b5102a5885f8664d0af410324d448/docker-compose.yml#L29-L44
• Documentation for this is here (descriptions of the environment settings are at the bottom).

2) Add a configuration approach.

• The application won't be too heavy on configuration, but it needs a solid approach for this and doesn't yet have it. To start with, you could use environment variables, added to the container environment using environment or env_file blocks in the docker-compose.yml under the application service. Documentation for those blocks is here and here. I would start by using a .env file that you include in a .gitignore and .dockerignore so that it isn't committed to the project or included in Docker images (see the docs here). You can include .env.sample file in the repository with the variable names and some recommended values (so long as they aren't sensitive).
• Once you have all that set up, you can reference them using os.getenv('SOME_VARIABLE', 'SOME_DEFAULT') throughout the Python project (see the Python docs for the os module). You can talk with @jonespm or me more later about optimizing configuration (which is a whole thing).

3) Set up the database connection in Django.

• The sqlite database is the default, and is currently managed here. The link there will take you to the specifics on adding the mysql database connection. You can also add look at the Placement Exams example here (which is pretty straightforward, you can ignore the test stuff now).
• The connection is just the beginning: next you'll need to do the data modeling, and set up models. I'd recommend getting familiar with the Django docs (which are good) and specifically the models layer and migrations.