Illegal instruction: 4 when running Django

Question

I made clean install of Django v1.11.10 now. When I run python manage.py runserver everything works fine. But when I try connect to Postgres database, I install

Answer 1

Blender's answer and this other question pointed to the problem, but when running the suggested command, I was getting the following error:

 Error: pg_config executable not found.

    pg_config is required to build psycopg2 from source.  Please add the directory
    containing pg_config to the $PATH or specify the full executable path with the
    option:

        python setup.py build_ext --pg-config /path/to/pg_config build ...

    or with the pg_config option in 'setup.cfg'.

As I have no clue about settings, configurations and so on, it took a while to find out how to do it. Here it is in case somebody else faces the same issue:

pip uninstall psycopg2

then

export PATH=$PATH:/Applications/Postgres.app/Contents/Versions/latest/bin/

then

pip install --no-binary :all: psycopg2

This solved the problem for me.