refactor: split tasks/supports/meetings into separate tables

app/models/task.py

@@ -0,0 +1,45 @@
+from sqlalchemy import Column, Integer, String, Text, DateTime, ForeignKey, Enum, Time
+from sqlalchemy.orm import relationship
+from sqlalchemy.sql import func
+from app.core.config import Base
+import enum
+
+class TaskStatus(str, enum.Enum):
+    OPEN = "open"
+    PENDING = "pending"
+    PROGRESSING = "progressing"
+    CLOSED = "closed"
+
+class TaskPriority(str, enum.Enum):
+    LOW = "low"
+    MEDIUM = "medium"
+    HIGH = "high"
+    CRITICAL = "critical"
+
+class Task(Base):
+    __tablename__ = "tasks"
+    
+    id = Column(Integer, primary_key=True, index=True)
+    title = Column(String(255), nullable=False)
+    description = Column(Text, nullable=True)
+    status = Column(Enum(TaskStatus), default=TaskStatus.OPEN)
+    priority = Column(Enum(TaskPriority), default=TaskPriority.MEDIUM)
+    
+    project_id = Column(Integer, ForeignKey("projects.id"), nullable=False)
+    milestone_id = Column(Integer, ForeignKey("milestones.id"), nullable=False)
+    reporter_id = Column(Integer, ForeignKey("users.id"), nullable=False)
+    assignee_id = Column(Integer, ForeignKey("users.id"), nullable=True)
+    created_by_id = Column(Integer, ForeignKey("users.id"), nullable=True)
+    
+    task_code = Column(String(64), nullable=True, unique=True, index=True)
+    depend_on = Column(Text, nullable=True)
+    estimated_effort = Column(Integer, nullable=True)
+    estimated_working_time = Column(Time, nullable=True)
+    started_on = Column(DateTime(timezone=True), nullable=True)
+    finished_on = Column(DateTime(timezone=True), nullable=True)
+    related_tasks = Column(Text, nullable=True)
+    
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), onupdate=func.now())
+    
+