Change timezone used for saving meetups and scheduling reminders

Description

Currently the meetup time and reminder schedules are stored in Local timezone of the host machine.
This creates issues when the bot is deployed on some cloud platform because the Local time for the host machine may be different.

Changes to be made

In meetup.go, replace instances where Local time is used, to use Indian time instead.

One such instance:-

bots/telegram-bot/meetup.go

Line 98 in e3920af

    
           Date:  time.Date(year, time.Month(month), day, hour, minutes, 0, 0, time.Local),

This might be helpful:- https://golang.org/pkg/time/#LoadLocation

First time contributors

Hi, If it is the first time that you contribute to the bot:

Write a comment in this issue thread to let other possible contributors know that you are working on this bug. For eg : Hey all, I would like to work on this issue., follow Contributing to the bot 🔥✨ and feel free to ask anything related to this issue ✌️

Hello! I would like to work on this issue.

@starkah Hey 👋. Thanks for showing your interest in this. Feel free to ask any queries while you work on it.