text: create table users (
  	user_id int unsigned AUTO_INCREMENT NOT NULL,
  	name varchar(100) NOT NULL,
  	email varchar(320) unique NOT NULL,          
  	mobileno varchar(10) unique NOT NULL,
  	profilepic varchar(100),
  	passwd char(32) NOT NULL,
  	about text,
  	creation_time timestamp NOT NULL,
  	is_active boolean NOT NULL DEFAULT 0,
  	hash_key char(32) NOT NULL,
  	primary key (user_id)
  );
  
  create table tags (
  	tag_id int unsigned AUTO_INCREMENT NOT NULL,
  	name varchar(50) NOT NULL,
  	primary key (tag_id)
  );
  
  create table questions (
  	q_id int unsigned AUTO_INCREMENT NOT NULL,
  	title varchar(50) NOT NULL,
  	description text NOT NULL,
  	creation_time timestamp NOT NULL,
  	user_id int unsigned NOT NULL,
  	foreign key (user_id) references users(user_id) on delete cascade on update cascade,
  	primary key (q_id)
  );
  
  create table answers (
  	a_id int unsigned AUTO_INCREMENT NOT NULL,
  	q_id int unsigned NOT NULL,
  	user_id int unsigned NOT NULL,
  	answer_time timestamp NOT NULL,
  	answer_text  text NOT NULL,
  	foreign key (user_id) references users(user_id) on delete cascade on update cascade,
  	foreign key (q_id) references questions(q_id) on delete cascade on update cascade,
  	primary key (a_id)
  );
  
  create table question_tags (
  	tag_id int unsigned NOT NULL,
  	q_id  int unsigned NOT NULL,
  	foreign key (tag_id) references tags(tag_id) on delete cascade on update cascade,
  	foreign key (q_id) references questions(q_id) on delete cascade on update cascade,
  	primary key (tag_id,q_id)
  );
  
  create table follows (
  	tag_id int unsigned NOT NULL,
  	user_id  int unsigned NOT NULL,
  	foreign key (tag_id) references tags(tag_id) on delete cascade on update cascade,
  	foreign key (user_id) references users(user_id) on delete cascade on update cascade,
  	primary key (tag_id,user_id)
  );
  