Guidance added for adding analytics to specific versions in the database

docs/db/analytics-definitions.md

@@ -1,12 +1,13 @@
 # Analytics definitions
 
-The `AnalyticsDefinitions` table contains details about supported analytics tools for adding analytics functionality to the site.
+The `AnalyticsDefinitions` table contains details about supported analytics tools for adding analytics functionality to the site. The `VersionAnalytic` table specifies which versions to apply the analytics to (default is to be applied to all versions).
 
 ## Relevant tables
 
 | Table Name                        | Description                          |
 | --------------------------------- | ------------------------------------ |
-| AnalyticsDefinitions         | Contains the pre-defined analytics providers |
+| AnalyticsDefinitions				| Contains the pre-defined analytics providers |
+| VersionAnalytic			        | Contains specified versions for using analytics |
 
 ### AnalyticsDefinitions
 
@@ -17,3 +18,14 @@ This table contains the details of each analytics provider that is available.
 - `DateModified` - The date the analytics have been created or amended
 - `Enabled` - Whether the analytics are switched on or not
 - `CookieControl` - Defines which cookie control is used, currently only supports Civica
+
+### VersionAnalytic
+
+This table contains the details of which analytics should be used on specific versions..
+
+- `VersionID` - The ID of the [version](../db/versions.md)
+- `AnalyticsDefinitionID` - The ID of the analytics definition from the `AnalyticsDefinitions` table
+
+!!! Note on versions
+    If you don't specify any versions the analytics tool will be applied to all of the versions. 
+