Can not run PostgreSQL after drop table
Main problem was that I could not run psql command under no user.
Output I received was:

psql: FATAL:  role "any role" does not exist


any role means that I tried to run psql under each user on my system(root,postgresql,my_user)

After all I haven't figured out what the problem was, I decided to reinstall PostgreSQL. 

And this process turned out rather hard to.

So if you have problems with deleting and reinstalling PostgreSQL, read on.

Here what I had to do.

echo "deb http://apt.postgresql.org/pub/repos/apt/ precise-pgdg main" &gt; /etc/apt/sources.list.d/pgdg.list

wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | sudo apt-key add -


sudo apt-get update

now we get error about missing postgresql-common
to fix it we need to install above package
lets determine its version

sudo apt-cache policy postgresql-common


and install it

sudo apt-get install postgresql-common=151.pgdg12.4+1


we can get error that postgresql-client-common not installed
so we need to do the same
determine it version

sudo apt-cache policy postgresql-client-common


and install

sudo apt-get install postgresql-client-common=151.pgdg12.4+1


after this we can install postgresql like this

sudo apt-get install postgresql-9.3 postgresql-contrib-9.3