GRAMEX-205 ⁃ ENH: MLHandler supports FBProphet for forecasting

[jaidevd]

"Prophet" is available as a valid model class in MLHandler now.

Usage

Use the following spec:

mlhandler/prophet:
    pattern: /prophet
    handler: MLHandler
    kwargs:
      model:
        class: Prophet
      xsrf_cookies: false

Download a sample dataset here

• Training:

curl -X POST "/prophet?_action=train&target_col=y" -d @train.json -H "Content-Type: application/json"
# {score: 0.33} Returns the MAE score

• Getting predictions against timestamps

curl -X POST "/prophet?_action=predict&target_col=y" -d @test.json -H "Content-Type: application/json"
# The timestamp column MUST be called "ds"

• Getting forecasts for n periods in the future

# Get a month's forecast, assuming daily data
curl -X GET "/prophet?_action=predict&n_perids=30"

To be merged after #547