Create model.md

Author: mishmosh

.github/ISSUE_TEMPLATE/model.md

@@ -0,0 +1,26 @@
+---
+name: Bug report for model
+about: Feedback or bug report for the epidemiological model and analysis.
+title: [model]
+labels: 'models'
+assignees: ''
+
+---
+
+<!--
+Please note: Any changes to the model have a huge impact on rapidly evolving hospital system & public health decisions. The current model has been in use for a while now, and it has been validated against other similar models, so any changes to the model must meet a very high bar.
+
+However, these 2 types of issue reports are very welcome:
+- Bugs causing this model to produce invalid results. In this case, please include details and a suggested fix.
+- If this model is producing a significantly different result than another well-known epidemiological model. In this case, please include proof of this difference and a suggested fix to our approach.
+
+For questions or early discussion, please join us in #chime-analysis in Slack instead.
+-->
+
+### Summary
+
+
+### Additional details
+
+
+### Suggested fix