サイト（掲示板）掲示板が表示されません。

[https://github.com/blobmon/simplechan]
上の掲示板をネット上に設置したのですが、ホーム画面は表示されるのですが、そこからクリックをして入ったら本来表示されるべきものが表示されません。クリックしたらこんなものが出てきます。

    psycopg2.OperationalError
OperationalError: FATAL:  Peer authentication failed for user "simplech_role"
Traceback (most recent call last)
File "/root/simplechan/venv/lib/python2.7/site-packages/flask/app.py", line 2309, in __call__
return self.wsgi_app(environ, start_response)
File "/root/simplechan/venv/lib/python2.7/site-packages/flask/app.py", line 2295, in wsgi_app
response = self.handle_exception(e)
File "/root/simplechan/venv/lib/python2.7/site-packages/flask/app.py", line 1741, in handle_exception
reraise(exc_type, exc_value, tb)
File "/root/simplechan/venv/lib/python2.7/site-packages/flask/app.py", line 2292, in wsgi_app
response = self.full_dispatch_request()
File "/root/simplechan/venv/lib/python2.7/site-packages/flask/app.py", line 1815, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/root/simplechan/venv/lib/python2.7/site-packages/flask/app.py", line 1718, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "/root/simplechan/venv/lib/python2.7/site-packages/flask/app.py", line 1813, in full_dispatch_request
rv = self.dispatch_request()
File "/root/simplechan/venv/lib/python2.7/site-packages/flask/app.py", line 1799, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "/root/simplechan/app/app/__init__.py", line 91, in mod_logs
handler = Handler()
File "/root/simplechan/app/app/handler.py", line 26, in __init__
self.con = psycopg2.connect("dbname='{}' user='{}'".format(app.config['DB_NAME'], app.config['DB_ROLE']) )
File "/root/simplechan/venv/lib/python2.7/site-packages/psycopg2/__init__.py", line 130, in connect
conn = _connect(dsn, connection_factory=connection_factory, **kwasync)

OperationalError: FATAL: Peer authentication failed for user "simplech_role"

The debugger caught an exception in your WSGI application. You can now look at the traceback which led to the error. 

To switch between the interactive traceback and the plaintext one, you can click on the "Traceback" headline. From the text traceback you can also create a paste of it. For code execution mouse-over the frame you want to debug and click on the console icon on the right side.

You can execute arbitrary Python code in the stack frames and there are some extra helpers available for introspection:

dump() shows all variables in the frame
dump(obj) dumps all that's known about the object

Brought to you by DON'T PANIC, your friendly Werkzeug powered traceback interpreter.

と表示されます。
何が原因でこういう風になったのでしょうか？

あと、サイトにもある通り"ffmpeg"をインストールしようと、activateしながら

  pip install ffmpeg

```と入力したら

```ここに言語を入力
    Could not find a version that satisfies the requirement subprocess (from ffmpeg) (from versions: )
No matching distribution found for subprocess (from ffmpeg)

と赤文字で表示されました。どうやったら、インストールできますか？