Added email.error_data column migration

no issue

- additional migration for the column added since the last 3.1 beta release to allow beta upgrades without rollbacks
- will be a no-op for upgrades from 3.0 as it's covered by `3.1/05-add-emails-table.js`

core/server/data/migrations/versions/3.1/10-add-email-error-data-column.js

@@ -0,0 +1,25 @@
+const commands = require('../../../schema').commands;
+
+module.exports.up = commands.createColumnMigration({
+    table: 'emails',
+    column: 'error_data',
+    dbIsInCorrectState(columnExists) {
+        return columnExists === true;
+    },
+    operation: commands.addColumn,
+    operationVerb: 'Adding'
+});
+
+module.exports.down = commands.createColumnMigration({
+    table: 'emails',
+    column: 'error_data',
+    dbIsInCorrectState(columnExists) {
+        return columnExists === false;
+    },
+    operation: commands.dropColumn,
+    operationVerb: 'Removing'
+});
+
+module.exports.config = {
+    transaction: true
+};