fix: Migration error message

Author: TomBursch

backend/migrations/versions/1d3c1e2061f6_datetime_in_planner.py

@@ -63,8 +63,9 @@ def upgrade():
 
     with op.batch_alter_table('planner', schema=None) as batch_op:
         batch_op.alter_column('cooking_date', nullable=False)
-        batch_op.drop_column('day')
+        batch_op.drop_constraint('pk_planner')
         batch_op.create_primary_key('pk_planner', ['recipe_id', 'cooking_date'])
+        batch_op.drop_column('day')
 
     # ### end Alembic commands ###
 
@@ -73,7 +74,8 @@ def downgrade():
     # ### commands auto generated by Alembic - please adjust! ###
     with op.batch_alter_table('planner', schema=None) as batch_op:
         batch_op.add_column(sa.Column('day', sa.INTEGER(), nullable=False))
-        batch_op.drop_column('cooking_date')
+        batch_op.drop_constraint('pk_planner')
         batch_op.create_primary_key('pk_planner', ['recipe_id', 'day'])
+        batch_op.drop_column('cooking_date')
 
     # ### end Alembic commands ###