Go: add dbscheme relations for overlay support

Author: nickrolfe

go/downgrades/b1341734d6870b105e5c9d168ce7dec25d7f72d0/go.dbscheme

@@ -0,0 +1,4 @@
+description: Add databaseMetadata and overlayChangedFiles relations
+compatibility: full
+databaseMetadata.rel: delete
+overlayChangedFiles.rel: delete

go/downgrades/b1341734d6870b105e5c9d168ce7dec25d7f72d0/old.dbscheme

@@ -43,6 +43,17 @@ externalData(
 snapshotDate(unique date snapshotDate : date ref);
 
 sourceLocationPrefix(varchar(900) prefix : string ref);
+
+/** Overlay support **/
+
+databaseMetadata(
+  string metadataKey: string ref,
+  string value: string ref
+);
+
+overlayChangedFiles(
+  string path: string ref
+);
 `)
 
 // Copied directly from the XML dbscheme

go/downgrades/b1341734d6870b105e5c9d168ce7dec25d7f72d0/upgrade.properties

@@ -36,6 +36,17 @@ snapshotDate(unique date snapshotDate : date ref);
 
 sourceLocationPrefix(varchar(900) prefix : string ref);
 
+/** Overlay support **/
+
+databaseMetadata(
+  string metadataKey: string ref,
+  string value: string ref
+);
+
+overlayChangedFiles(
+  string path: string ref
+);
+
 
 /*
  * XML Files