Fix based on feedback

Author: brfrn169

core/src/main/java/com/scalar/db/storage/jdbc/JdbcAdmin.java

@@ -425,9 +425,7 @@ private TableMetadata mergeSourceTableMetadata(
       builder.addSecondaryIndex(secondaryIndex);
     }
     for (String secondaryIndex : rightSourceTableMetadata.getSecondaryIndexNames()) {
-      if (!primaryKeyColumns.contains(secondaryIndex)) {
-        builder.addSecondaryIndex(secondaryIndex);
-      }
+      builder.addSecondaryIndex(secondaryIndex);
     }
 
     return builder.build();

core/src/test/java/com/scalar/db/storage/jdbc/JdbcAdminTest.java

@@ -412,6 +412,7 @@ public void getTableMetadata_VirtualTableExists_ShouldReturnMergedTableMetadata(
             .addColumn("col1", DataType.BOOLEAN)
             .addColumn("col2", DataType.DOUBLE)
             .addColumn("col3", DataType.BLOB)
+            .addSecondaryIndex("ck1")
             .addSecondaryIndex("col1")
             .addSecondaryIndex("col2")
             .build();
@@ -429,6 +430,7 @@ public void getTableMetadata_VirtualTableExists_ShouldReturnMergedTableMetadata(
             .addColumn("col4", DataType.FLOAT)
             .addColumn("col5", DataType.DATE)
             .addColumn("col6", DataType.TIMESTAMP)
+            .addSecondaryIndex("ck2")
             .addSecondaryIndex("col4")
             .build();
 
@@ -463,7 +465,8 @@ public void getTableMetadata_VirtualTableExists_ShouldReturnMergedTableMetadata(
     assertThat(result.getColumnDataType("col4")).isEqualTo(DataType.FLOAT);
     assertThat(result.getColumnDataType("col5")).isEqualTo(DataType.DATE);
     assertThat(result.getColumnDataType("col6")).isEqualTo(DataType.TIMESTAMP);
-    assertThat(result.getSecondaryIndexNames()).containsExactlyInAnyOrder("col1", "col2", "col4");
+    assertThat(result.getSecondaryIndexNames())
+        .containsExactlyInAnyOrder("ck1", "ck2", "col1", "col2", "col4");
   }
 
   @Test