Fix missing albumMessageId.

SignalMessaging/environment/migrations/OWS113MultiAttachmentMediaMessages.swift

@@ -15,7 +15,9 @@ public class OWS113MultiAttachmentMediaMessages: OWSDatabaseMigration {
     // Increment a similar constant for each migration.
     @objc
     class func migrationId() -> String {
-        return "113"
+        // NOTE: that we use .1 since there was a bug in the logic to
+        //       set albumMessageId.
+        return "113.1"
     }
 
     override public func runUp(completion: @escaping OWSDatabaseMigrationCompletion) {

SignalServiceKit/src/Messages/Attachments/TSAttachment.m

@@ -58,6 +58,7 @@ NSUInteger const TSAttachmentSchemaVersion = 4;
     _contentType = contentType;
     _sourceFilename = sourceFilename;
     _caption = caption;
+    _albumMessageId = albumMessageId;
 
     _attachmentSchemaVersion = TSAttachmentSchemaVersion;
 
@@ -126,6 +127,7 @@ NSUInteger const TSAttachmentSchemaVersion = 4;
     }
     _contentType = contentType;
     _caption = pointer.caption;
+    _albumMessageId = pointer.albumMessageId;
 
     _attachmentSchemaVersion = TSAttachmentSchemaVersion;