Add ability to specify prefered gravatar email for user profile

Stackalytics does not ensure configuration email order during
processing. Thus additional field is required to ensure a proper
email is used to compile gravatar url.

Change-Id: I01805b1dec76cd1abd57a82f75cc158696f5c165
Signed-off-by: Andrii Ostapenko <aostapenko@stackalytics.io>

etc/default_data.json

@@ -3530,6 +3530,7 @@
                     "end_date": null
                 }
             ],
+            "gravatar_email": "anost1986@gmail.com",
             "user_name": "Andrii Ostapenko",
             "emails": ["aostapenko@mirantis.com", "andrey_ostapenko@symantec.com", "ao129q@att.com",
                        "andrii.ostapenko@att.com", "anost1986@gmail.com", "aostapenko@stackalytics.io"]

stackalytics/dashboard/static/js/stackalytics-ui.js

@@ -370,6 +370,8 @@ function extendWithGravatar(record, image_size) {
     var gravatar = "stackalytics";
     if (record.author_email) {
         gravatar = record.author_email;
+    } else if (record.gravatar_email) {
+        gravatar = record.gravatar_email;
     } else if (record.emails && record.emails.length > 0) {
         gravatar = record.emails[0];
     } else if (record.user_id) {

stackalytics/processor/schema.py

@@ -36,6 +36,9 @@ default_data = {
                     "user_name": {
                         "type": "string"
                     },
+                    "gravatar_email": {
+                        "type": "string"
+                    },
                     "emails": {
                         "type": "array",
                         "items": {