When we get complaints we'd like to know how many we get in a day or other date range, so if there is a spike in complaints we can act on it.

Add new endpoint to return the number of complaints in a date range.

Unit tests to follow in the next commit.

app/complaint/complaint_schema.py

@@ -0,0 +1,11 @@
+
+complaint_count_request = {
+    "$schema": "http://json-schema.org/draft-04/schema#",
+    "description": "complaint count request schema",
+    "type": "object",
+    "title": "Complaint count request",
+    "properties": {
+        "start_date": {"type": ["string", "null"], "format": "datetime"},
+        "end_date":  {"type": ["string", "null"], "format": "datetime"},
+    }
+}