Error: pg_config executable not found

Peguei um projeto com backend em phyton... e quando rodei o comando "pip install" deu o erro:

Collecting psycopg2 (from django-toolbelt==0.0.1->-r requirements.txt (line 7))
  Downloading psycopg2-2.6.1.tar.gz (371kB)
    100% |################################| 372kB 652kB/s
    Complete output from command python setup.py egg_info:
    running egg_info
    creating pip-egg-info\psycopg2.egg-info
    writing pip-egg-info\psycopg2.egg-info\PKG-INFO
    writing top-level names to pip-egg-info\psycopg2.egg-info\top_level.txt
    writing dependency_links to pip-egg-info\psycopg2.egg-info\dependency_links.txt
    writing manifest file 'pip-egg-info\psycopg2.egg-info\SOURCES.txt'
    warning: manifest_maker: standard file '-c' not found

    Error: pg_config executable not found.

    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'.

    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in C:\Users\Adriano\AppData\Local\Temp\pip-build-ihjedt2y\psycopg2

Eu já tinha o PostgreSQL instalado, caso você não tenha, instale-o.
Depois adicione no PATH (variável de ambiente) a pasta bin que fica dentro da pasta de instalação do PostgreSQL

Pronto, rode de novo o comando e funcionará :)