Add created column to blob upload

Fixes first half of #1054

data/database.py

@@ -786,6 +786,7 @@ class BlobUpload(BaseModel):
   storage_metadata = JSONField(null=True, default={})
   chunk_count = IntegerField(default=0)
   uncompressed_byte_count = IntegerField(null=True)
+  created = DateTimeField(default=datetime.now, index=True)
 
   class Meta:
     database = db

data/migrations/versions/88e0f440a2f_add_created_field_to_the_blobupload_.py

@@ -0,0 +1,27 @@
+"""Add created field to the BlobUpload table
+
+Revision ID: 88e0f440a2f
+Revises: 403d02fea323
+Create Date: 2015-12-14 15:19:11.825279
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '88e0f440a2f'
+down_revision = '403d02fea323'
+
+from alembic import op
+import sqlalchemy as sa
+
+def upgrade(tables):
+    ### commands auto generated by Alembic - please adjust! ###
+    op.add_column('blobupload', sa.Column('created', sa.DateTime(), nullable=False, server_default=sa.text('now()')))
+    op.create_index('blobupload_created', 'blobupload', ['created'], unique=False)
+    ### end Alembic commands ###
+
+
+def downgrade(tables):
+    ### commands auto generated by Alembic - please adjust! ###
+    op.drop_index('blobupload_created', table_name='blobupload')
+    op.drop_column('blobupload', 'created')
+    ### end Alembic commands ###