Comenzando a utilizar SQLAlchemy

Tuve que reescribir bastante para lograrlo, pero ya funciona :3

files/models.py

@@ -0,0 +1,64 @@
+from flask_sqlalchemy import SQLAlchemy
+from datetime import datetime
+
+db = SQLAlchemy()
+
+
+class User(db.Model):
+    __tablename__ = 'users'
+    id = db.Column(db.Integer, primary_key=True)
+    username = db.Column(db.String, unique=True, nullable=False)
+    password = db.Column(db.String, nullable=False)
+
+    def __init__(self, username=None, password=None):
+        self.username = username
+        self.password = password
+
+    def __repr__(self):
+        return f'<User {self.username}>'
+
+
+class Message(db.Model):
+    __tablename__ = 'messages'
+    id = db.Column(db.Integer, primary_key=True)
+    name = db.Column(db.String, nullable=False)
+    email = db.Column(db.String, nullable=False)
+    message = db.Column(db.Text, nullable=False)
+    sended = db.Column(db.DateTime, default=datetime.utcnow())
+
+    def __init__(self, name=None, email=None, message=None):
+        self.name = name
+        self.email = email
+        self.message = message
+
+    def __repr__(self):
+        return f'<Message from:{self.name} message:{self.message}>'
+
+
+class File(db.Model):
+    __tablename__ = 'files'
+    id = db.Column(db.Integer, primary_key=True)
+    filename = db.Column(db.String, nullable=False)
+    private = db.Column(db.Integer, nullable=False)
+    category_id = db.Column(db.Integer, db.ForeignKey('categories.id'), nullable=False)
+
+    def __init__(self, filename=None, private=None, category_id=None):
+        self.filename = filename
+        self.private = private
+        self.category_id = category_id
+
+    def __repr__(self):
+        return f'<File name:{self.filename}>'
+
+
+class Category(db.Model):
+    __tablename__ = 'categories'
+    id = db.Column(db.Integer, primary_key=True)
+    name = db.Column(db.String, nullable=False)
+    files = db.relationship('File', backref='category', lazy=True)
+
+    def __init__(self, name=None):
+        self.name = name
+
+    def __repr__(self):
+        return f'<Category name:{self.name}>'