Add migration

migrations/versions/4e482c47e519_.py

@@ -0,0 +1,39 @@
+"""empty message
+
+Revision ID: 4e482c47e519
+Revises: 900758871713
+Create Date: 2018-05-27 22:38:16.507155
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '4e482c47e519'
+down_revision = '900758871713'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_table('dependency',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('depender_id', sa.Integer(), nullable=True),
+    sa.Column('package_id', sa.Integer(), nullable=True),
+    sa.Column('meta_package_id', sa.Integer(), nullable=True),
+    sa.Column('optional', sa.Boolean(), nullable=False),
+    sa.ForeignKeyConstraint(['depender_id'], ['package.id'], ),
+    sa.ForeignKeyConstraint(['meta_package_id'], ['meta_package.id'], ),
+    sa.ForeignKeyConstraint(['package_id'], ['package.id'], ),
+    sa.PrimaryKeyConstraint('id'),
+    sa.UniqueConstraint('depender_id', 'package_id', 'meta_package_id', name='_dependency_uc')
+    )
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_table('dependency')
+    # ### end Alembic commands ###