"""star_a_project

Revision ID: c34f4b09ef18

Revises: 8a5d68f74beb

Create Date: 2017-07-07 00:08:18.257075

"""

# revision identifiers, used by Alembic.

revision = 'c34f4b09ef18'

down_revision = '8a5d68f74beb'

from alembic import op

import sqlalchemy as sa

def upgrade():

    ''' Add a new table to store data about who starred which project '''

    op.create_table(

        'stargazers',

        sa.Column('id', sa.Integer, primary_key=True),

        sa.Column(

            'project_id',

            sa.Integer,

            sa.ForeignKey(

                'projects.id', onupdate='CASCADE', ondelete='CASCADE'),

            nullable=False,

            index=True,

        ),

        sa.Column(

            'user_id',

            sa.Integer,

            sa.ForeignKey('users.id', onupdate='CASCADE', ondelete='CASCADE'),

            nullable=False,

        )

    )

    op.create_unique_constraint(

        constraint_name='uq_stargazers_project_id_user_id_key',

        table_name='stargazers',

        columns=['project_id', 'user_id']

    )

def downgrade():

    ''' Remove the stargazers table from the database '''

    op.drop_constraint(

        constraint_name='uq_stargazers_project_id_user_id_key',

        table_name='stargazers'

    )

    op.drop_table('stargazers')