text: from enum import unique
  from devnode import db, app
  from flask_login import UserMixin
  from devnode import login_manager
  from itsdangerous import TimedJSONWebSignatureSerializer as Serializer
  from datetime import datetime
  
  
  @login_manager.user_loader
  def load_user(user_id):
      return User.query.get(int(user_id))
  
  association_table = db.Table('association',
      db.Column('skill_id', db.Integer, db.ForeignKey('skill.id'), primary_key=True),
      db.Column('user_id', db.Integer, db.ForeignKey('user.id'), primary_key=True)
  )
  
  class User(db.Model, UserMixin):
      id = db.Column(db.Integer, primary_key=True)
      username = db.Column(db.String(20), unique=True, nullable=False)
      email = db.Column(db.String(80), unique=True, nullable=False)
      profile_image_file = db.Column(db.String(20), nullable=False, default='default_profile_pic.jpg')
      cover_image_file = db.Column(db.String(20), nullable=False, default='default_cover_pic.jpg')
      password = db.Column(db.String(60), nullable=False)
      confirmed = db.Column(db.Boolean, nullable=False, default=False)
      about = db.Column(db.Text, nullable=False, default='Devnode Member')
      designation = db.Column(db.String(100), nullable=False, default='Devnode Member')
      branch = db.Column(db.String(100), default=None)
      year = db.Column(db.Integer,default=None)
      discord_id = db.Column(db.String(120), unique=True)
      twitter_id = db.Column(db.String(120), unique=True)
      github_id = db.Column(db.String(120), unique=True)
      linkedin_id = db.Column(db.String(120), unique=True)
      skills = db.relationship('Skill', secondary=association_table, lazy='subquery',
          backref=db.backref('users_associated', lazy=True))
      posts = db.relationship('Post', backref='author', lazy=True)
  
      def get_token(self, expires_sec=1800):
          s = Serializer(app.config['SECRET_KEY'], expires_sec)
          return s.dumps({'user_id' : self.id}).decode('utf-8')
  
      @staticmethod
      def verify_token(token):
          s = Serializer(app.config['SECRET_KEY'])
          try:
              user_id = s.loads(token)['user_id']
          except:
              return None
          return User.query.get(user_id)
  
  
  
      def __repr__(self):
          return f"User'{self.username}', '{self.email}'"
  
  class Skill(db.Model):
      id = db.Column(db.Integer, primary_key=True)
      name = db.Column(db.String(20), unique=True)
  
  
  
  
  class Post(db.Model):
      id = db.Column(db.Integer, primary_key=True)
      title = db.Column(db.String(120), nullable=False)
      content= db.Column(db.Text, nullable=False)
      date_posted = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)
      category = db.Column(db.String(120), nullable=False)
      last_date = db.Column(db.String(80), nullable=False)
      persons_required = db.Column(db.Integer, nullable=False)
      user_id=db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)
  
      def __repr__(self):
          return f"User'{self.title}', '{self.date_posted}'"