Added amp_gtag_id setting migration & default

refs #11980

This lays the ground for the rest of the work surrounding Google
Analytics in AMP.

core/server/data/migrations/versions/3.25/02-add-amp-gtag-id-setting.js

@@ -0,0 +1,20 @@
+const logging = require('../../../../../shared/logging');
+
+module.exports = {
+    config: {
+        transaction: true
+    },
+
+    async up({transacting: knex}) {
+        logging.info('Updating amp_gtag_id setting to amp group');
+        await knex('settings')
+            .update({
+                group: 'amp'
+            })
+            .where({
+                key: 'amp_gtag_id'
+            });
+    },
+
+    async down() {}
+};

core/server/data/schema/default-settings.json

@@ -337,6 +337,10 @@
                 "isIn": [["true", "false"]]
             },
             "type": "boolean"
+        },
+        "amp_gtag_id": {
+            "defaultValue": null,
+            "type": "string"
         }
     },
     "labs": {

test/regression/api/canary/admin/settings_spec.js

@@ -56,6 +56,7 @@ const defaultSettingsKeyTypes = [
     {key: 'mailgun_domain', type: 'bulk_email'},
     {key: 'mailgun_base_url', type: 'bulk_email'},
     {key: 'amp', type: 'blog'},
+    {key: 'amp_gtag_id', type: 'blog'},
     {key: 'labs', type: 'blog'},
     {key: 'slack', type: 'blog'},
     {key: 'unsplash', type: 'blog'},

test/regression/api/v2/admin/settings_spec.js

@@ -53,6 +53,7 @@ const defaultSettingsKeyTypes = [
     {key: 'mailgun_domain', type: 'bulk_email'},
     {key: 'mailgun_base_url', type: 'bulk_email'},
     {key: 'amp', type: 'blog'},
+    {key: 'amp_gtag_id', type: 'blog'},
     {key: 'labs', type: 'blog'},
     {key: 'slack', type: 'blog'},
     {key: 'unsplash', type: 'blog'},

test/regression/api/v3/admin/settings_spec.js

@@ -56,6 +56,7 @@ const defaultSettingsKeys = [
     'mailgun_domain',
     'mailgun_base_url',
     'amp',
+    'amp_gtag_id',
     'labs',
     'slack',
     'unsplash',

test/unit/data/schema/integrity_spec.js

@@ -23,7 +23,7 @@ describe('DB version integrity', function () {
     // Only these variables should need updating
     const currentSchemaHash = '134c9de4e59b31ec6b73f03638a01396';
     const currentFixturesHash = '3d942c46e8487c4aee1e9ac898ed29ca';
-    const currentSettingsHash = 'b0291920e168e74cf63a1919cd594fd6';
+    const currentSettingsHash = 'a4ac78d3810175428b4833645231d6d5';
 
     // If this test is failing, then it is likely a change has been made that requires a DB version bump,
     // and the values above will need updating as confirmation