add model to sql datamodel

[peterdudfield]

Detailed Description

We now want to run multiple ml models from one site, so we need to tag the forecast with the model name

Context

• some queries just look at foreacstvalue table, so dont want to do many joins

Possible Implementation

There are a few options

1. Add new model table and join to forecast table
2. Add new model table join to forecastvalue table
3. Add columns model_name and model_version to forecastvalue table

I think we should go for 3, to keep it simple for the moment

We would also need to

• update forecast app to save the model version
• update read function in api to
• update internal dashboard

[peterdudfield]

decided actually to go with option 3. This will make the read function the faster I think

[peterdudfield]

Once #85 is deployed, it would be great to back fill the last month of forecasts, attaching them to the model. This can be done with some SQL code

[peterdudfield]

Ill makr this as complete for now, but might need to run migrations still