Creating ensemble submission

Steps for creating and submitting a real-time ensemble forecast. This set of steps needs to be performed every Monday evening after 5pm (or whenever the last models get pushed) and before 11:59pm.

1. Check compatibility and merge all relevant pull requests on the master branch.
2. Make sure you are on the master branch of the cdc-flusight-ensemble repository.
3. Pull all recent commits.
4. Check to see if all component models have current forecasts. If not, the ensemble will still build, but send email to nudge contributors.
5. Run the make-real-time-ensemble-forecast-file.R script with the following command from root cdc-flusight-ensemble directory: Rscript ./scripts/make-real-time-ensemble-forecast-file.R <CURRENT WEEK> where <CURRENT WEEK> is the current EPIWeek as an integer (i.e. 42). This should generate a set of all ensemble forecast files, including one that is saved in model-forecasts/submissions/target-type-based-weights, and a multi-page PDF file with plots in the model-forecasts/submissions/target-type-based-weights/plots/ folder.
6. Look at the plots to make sure nothing looks terribly out of alignment.
7. Commit the plots file and all new ensemble files to your local git repository. Your commit message MUST include: "trigger build" in lowercase letters (Travis is case-sensitive). i.e. "trigger build week 42".
8. Push all files to the master branch.
9. Submit the submission file to the CDC: Go to https://predict.cdc.gov and log in. Click Go to project on the current FluSight Challenge on the dashboard and click to Submit on the left panel. Upload this week's .csv file in the model-forecasts/submissions/target-type-based-weights folder.
10. Tweet out new forecasts!