Improvements to Slack bot (to message new users)

[ye-susan]

Overview

This issue is a continuation of issue #154. The slackbot for sending new users (account created 30 days or less) messages and reminders currently has the functionality to

• query the db for user accounts that are <= 30 days old
• message user from markdown via Slackbot direct message

Action Items -- Improvements Required

• check if user has already attended meetings, so they won't receive the messages
• this slackbot is currently not linked to cron to be run daily
• need a way to determine that we've already messaged user so they won't receive message again

Resources

This PR: https://github.com/hackforla/VRMS/pull/382/files and the original issue #154 And feel free to slack me if any questions arise in regard to the code that's currently in the PR