add migrations component

app.py

@@ -1,5 +1,6 @@
 import os
 from flask import Flask, render_template, redirect
+from flask_migrate import Migrate
 from misc import datetime, date, time, currDay
 from db import (db, Period, Task, Event)
 from forms import (TaskForm, EventForm, PeriodForm)
@@ -14,6 +15,11 @@ app.config['SQLALCHEMY_DATABASE_URI'] =\
 app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
 db.init_app(app)
 
+# init migration
+migrate = Migrate()
+migrate.init_app(app, db)
+
+
 from auth import auth as auth_blueprint
 app.register_blueprint(auth_blueprint)