TDL-14271 Facebook leads table

_integration-schemas/facebook-ads/foreign-keys.md

@@ -73,6 +73,7 @@ foreign-keys:
       - table: "campaigns"
         subtable: "ads"
         join-on: "id"
+      - table: "leads"
 
   - id: "campaign-id"
     attribute: "campaign_id"

_integration-schemas/facebook-ads/leads.md

@@ -0,0 +1,59 @@
+---
+tap: "facebook-ads"
+version: "1"
+
+name: "leads"
+doc-link: https://developers.facebook.com/docs/marketing-api/guides/lead-ads/
+singer-schema: https://github.com/singer-io/tap-facebook/blob/master/tap_facebook/schemas/leads.json
+description: |
+  The `leads` table contains information about Lead Ads in your Facebook account.
+
+replication-method: "Key-based Incremental"
+
+api-method:
+  name: "Retrieving Leads - Bulk Read"
+  doc-link: "https://developers.facebook.com/docs/marketing-api/guides/lead-ads/retrieving#bulk-read"
+
+attributes:
+  - name: "id"
+    type: "string"
+    description: "The lead ID." 
+    primary-key: true
+
+  - name: "ad_id"
+    type: "string"
+    description: "The ad ID." 
+
+  - name: "form_id"
+    type: "string"
+    description: "The form ID." 
+
+  - name: "created_time"
+    type: "date-time"
+    description: "The time the lead was created." 
+    replication-key: true
+
+  - name: "field_data"
+    type: "array"
+    description: "" 
+    subattributes:
+
+      - name: "items"
+        type: "object"
+        description: ""
+        subattributes:
+
+          - name: "properties"
+            type: "string"
+            description: ""
+
+          - name: "values"
+            type: "array"
+            description: ""
+            subattributes:
+
+              - name: "items"
+                type: "string"
+                description: ""
+
+---