Add Merkle Id prebid userId submodule

dev-docs/modules/userId.md

@@ -27,6 +27,7 @@ The User ID module supports multiple ways of establishing pseudonymous IDs for u
 * **IntentIQ ID** – An identity resolution pioneer, Intent IQ enables its partners to confidently identify clients and prospects who interact with their sites, apps and their brick and mortar establishments, whether across their various screens or in person.
 * **LiveIntent ID** – a user identifier tied to an active, encrypted email in our graph and functions in cookie-challenged environments and browsers.
 * **Lotame Panorama ID** - a people-based identifier available across all browsers -- including when third-party cookies are not available -- to connect and activate first, second, and third party data for programmatic advertising.
+* **Merkle Merkury ID** - Merkury enables marketers, media owners, and publishers to own, build, and control a cookie-less Private Identity Graph. Merkury uses an organization’s first-party CRM data and valuable interactions such as logins, outbound email campaigns and media reach to create and grow a universe of person-based IDs for cross-channel targeting, personalization, measurement and more.
 * **Parrable ID** - an encrypted pseudonymous ID that is consistent across all browsers and webviews on a device for every publisher the device visits.  This module contacts Parrable to obtain the Parrable EID belonging to the specific device which can then be used by the bidder.
 * **PubCommon ID** – an ID is generated on the user’s browser and stored for later use on this publisher’s domain.
 * **Quantcast ID** - an ID independent of third-party cookies for publishers with Quantcast Measure tag.      
@@ -72,7 +73,7 @@ of sub-objects. The table below has the options that are common across ID system
 {: .table .table-bordered .table-striped }
 | Param under userSync.userIds[] | Scope | Type | Description | Example |
 | --- | --- | --- | --- | --- |
-| name | Required | String | May be: `"britepoolId"`, `"criteo"`, `"id5id"`, `identityLink`, `"intentIqId"`, `"liveIntentId"`, `"lotamePanoramaId"`, `"parrableId"`, `"quantcastId"`, `"netId"`, `"pubCommonId"`, `"unifiedId"`, `"zeotapIdPlus"` | `"unifiedId"` |
+| name | Required | String | May be: `"britepoolId"`, `"criteo"`, `"id5id"`, `identityLink`, `"intentIqId"`, `"liveIntentId"`, `"lotamePanoramaId"`, `"merkleId"`, `"parrableId"`, `"quantcastId"`, `"netId"`, `"pubCommonId"`, `"unifiedId"`, `"zeotapIdPlus"` | `"unifiedId"` |
 | params | Based on User ID sub-module | Object | | |
 | storage | Optional | Object | The publisher can specify some kind of local storage in which to store the results of the call to get the user ID. This can be either cookie or HTML5 storage. This is not needed when `value` is specified or the ID system is managing its own storage | |
 | storage.type | Required | String | Must be either `"cookie"` or `"html5"`. This is where the results of the user ID will be stored. | `"cookie"` |
@@ -593,6 +594,34 @@ pbjs.setConfig({
 });
 {% endhighlight %}
 
+### Merkle ID
+
+[Merkury by Merkle](https://merkury.merkleinc.com/contact) enables marketers, media owners, and publishers to own, build, and control a cookie-less Private Identity Graph. Merkury uses an organization’s first-party CRM data and valuable interactions such as logins, outbound email campaigns and media reach to create and grow a universe of person-based IDs for cross-channel targeting, personalization, measurement and more.
+
+#### Merkury by Merkle ID Examples
+
+Publisher stores Merkury by Merkle in local storage for 30 days
+
+{% highlight javascript %}
+pbjs.setConfig({
+    userSync: {
+        userIds: [{
+        name: 'merkleId',
+        params: {
+          ptk: 'example',
+          pubid: 'EXAMPLE'
+        },
+        storage: {
+          type: 'html5',
+          name: 'merkleId',
+          expires: 30
+        }
+      }]
+    }
+});
+{% endhighlight %}
+
+
 ### Parrable ID
 
 The Parrable ID is a Full Device Identifier that can be used to identify a device across different browsers and webviews on a single device including browsers that have third party cookie restrictions.