diff --git a/rhodecode/__init__.py b/rhodecode/__init__.py
--- a/rhodecode/__init__.py
+++ b/rhodecode/__init__.py
@@ -51,7 +51,7 @@ PYRAMID_SETTINGS = {}
 EXTENSIONS = {}
 
 __version__ = ('.'.join((str(each) for each in VERSION[:3])))
-__dbversion__ = 61  # defines current db version for migrations
+__dbversion__ = 62  # defines current db version for migrations
 __platform__ = platform.system()
 __license__ = 'AGPLv3, and Commercial License'
 __author__ = 'RhodeCode GmbH'
diff --git a/rhodecode/lib/dbmigrate/versions/062_version_4_5_0.py b/rhodecode/lib/dbmigrate/versions/062_version_4_5_0.py
new file mode 100644
--- /dev/null
+++ b/rhodecode/lib/dbmigrate/versions/062_version_4_5_0.py
@@ -0,0 +1,31 @@
+import logging
+
+from sqlalchemy import Column, MetaData, Unicode
+
+from rhodecode.lib.dbmigrate.versions import _reset_base
+
+log = logging.getLogger(__name__)
+
+
+def upgrade(migrate_engine):
+    """
+    Upgrade operations go here.
+    Don't create your own engine; bind migrate_engine to your metadata
+    """
+    _reset_base(migrate_engine)
+    from rhodecode.lib.dbmigrate.schema import db_4_5_0_0 as db
+
+    # Add shadow merge ref column to pull request table.
+    pr_table = db.PullRequest.__table__
+    pr_col = Column('shadow_merge_ref', Unicode(255), nullable=True)
+    pr_col.create(table=pr_table)
+
+    # Add shadow merge ref column to pull request version table.
+    pr_version_table = db.PullRequestVersion.__table__
+    pr_version_col = Column('shadow_merge_ref', Unicode(255), nullable=True)
+    pr_version_col.create(table=pr_version_table)
+
+
+def downgrade(migrate_engine):
+    meta = MetaData()
+    meta.bind = migrate_engine