Build initial DB Models and migration

[mackcooper1408]

This is blocked by the research to define the initial DB schema #29

Context

Let's start putting the models together for our api to begin working with real data!

Definition of Done

1. SQLAlchemy models are created that match DB schema definitions
2. Pydantic Schemas are created that utilize the SQLAlchemy models
3. Alembic migrations have been generated and run to get the models stored into a local db and ready to store into a production db
4. If dummy models and schemas exist in the code still from the initial setup, they should be deleted cleaned up accordingly

Engineering Details

• See this guide for a reminder on building SQLAlchemy models and Pydantic Schemas
• see this guide for a reminder on generating Alembic migrations