programs: add the model for tags

[MIGRATION] This commit contains a new version of the schema.

app/models/__init__.py

@@ -4,3 +4,4 @@ from app.models.forum import Forum
 from app.models.topic import Topic
 from app.models.notification import Notification
 from app.models.program import Program
+from app.models.tag import Tag

app/models/program.py

@@ -19,6 +19,8 @@ class Program(Post):
     thread = db.relationship('Thread', foreign_keys=thread_id,
         back_populates='owner_program')
 
+    tags = db.relationship('Tag', back_populates='post', lazy='joined')
+
     # TODO: Number of views, statistics, attached files, etc
 
     def __init__(self, author, title, thread):

app/models/tag.py

@@ -0,0 +1,15 @@
+from app import db
+
+class Tag(db.Model):
+    __tablename__ = 'tag'
+    id = db.Column(db.Integer, primary_key=True)
+
+    # Tagged post
+    post_id = db.Column(db.Integer, db.ForeignKey('post.id'), index=True)
+    post = db.relationship('Post', back_populates='tags', foreign_keys=post_id)
+    # Tag name
+    name = db.Column(db.String(64), index=True)
+
+    def __init__(self, post, tag):
+        self.post = post
+        self.tag = tag

migrations/versions/1de8b6b6aed8_add_tags_for_programs.py

@@ -0,0 +1,38 @@
+"""add tags for programs
+
+Revision ID: 1de8b6b6aed8
+Revises: fcf53f1a14e3
+Create Date: 2022-05-19 18:50:12.894735
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '1de8b6b6aed8'
+down_revision = 'fcf53f1a14e3'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_table('tag',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('post_id', sa.Integer(), nullable=True),
+    sa.Column('name', sa.String(length=64), nullable=True),
+    sa.ForeignKeyConstraint(['post_id'], ['post.id'], ),
+    sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_tag_name'), 'tag', ['name'], unique=False)
+    op.create_index(op.f('ix_tag_post_id'), 'tag', ['post_id'], unique=False)
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_index(op.f('ix_tag_post_id'), table_name='tag')
+    op.drop_index(op.f('ix_tag_name'), table_name='tag')
+    op.drop_table('tag')
+    # ### end Alembic commands ###