To run the Flask API inside of a container, the Docker image must exist inside of Azure Container Registry
docker build -t name_of_docker_image_tag .
az acr create --name name_of_acr --resource-group name_of_rg --sku Standard
az acr login --name name_of_acr
docker tag name_of_docker_image_tag name_of_acr.azurecr.io/azureapi/flask
docker push name_of_acr.azurecr.io/azureapi/flask