已经有了啊。数据库我也查询了，状态都是小写的：
```
# revision identifiers, used by Alembic.
revision = '616677b3122c'
down_revision = 'b96ad24de868'
branch_labels = None
depends_on = None

def upgrade():
# ### commands auto generated by Alembic - please adjust! ###
op.create_table('approval',
sa.Column('id', sa.Integer(), nullable=False),
sa.Column('content_type', sa.String(length=50), nullable=False),
sa.Column('content_id', sa.Integer(), nullable=False),
sa.Column('submitter_id', sa.Integer(), nullable=False),
sa.Column('reviewer_id', sa.Integer(), nullable=True),
sa.Column('status', sa.Enum('pending', 'approved', 'rejected', name='approval_status'), nullable=True),
sa.Column('submit_time', sa.DateTime(), nullable=True),
sa.Column('review_time', sa.DateTime(), nullable=True),
sa.Column('review_comment', sa.Text(), nullable=True),
sa.ForeignKeyConstraint(['reviewer_id'], ['user.id'], ),
sa.ForeignKeyConstraint(['submitter_id'], ['user.id'], ),
sa.PrimaryKeyConstraint('id'),
sa.UniqueConstraint('content_type', 'content_id')
)
with op.batch_alter_table('user', schema=None) as batch_op:
batch_op.add_column(sa.Column('avatar', sa.String(length=120), nullable=True))

# ### end Alembic commands ###
```