django.db.utils.OperationalError：无法连接到服务器：连接被拒绝

我找到了一个 Django 项目，但未能通过以下方式在 Docker 容器中运行：

1. git clone https://github.com/hotdogee/django-blast.git

2. $ cat requirements.txt在此文件中，必须更新以下依赖项：

   • 海带==3.0.30
   • psycopg2==2.8.6

我有以下 Dockerfile：

FROM python:2
ENV PYTHONUNBUFFERED=1
WORKDIR /code
COPY requirements.txt /code/
RUN pip install -r requirements.txt
COPY . /code/

因为docker-compose.yml我使用：

version: "3"

services:
  db:
    image: postgres
    volumes:
      - ./data/db:/var/lib/postgresql/data
    environment:
      - POSTGRES_DB=postgres
      - POSTGRES_USER=postgres
      - POSTGRES_PASSWORD=postgres
  web:
    build: .
    command: python manage.py runserver 0.0.0.0:8000
    volumes:
      - .:/code
    ports:
      - "8000:8000"
    depends_on:
      - db

接下来，我遇到了这个错误：

$ docker-compose build
...

web_1  | System check identified no issues (0 silenced).
web_1  | Unhandled exception in thread started by <function wrapper at 0x7f265ed26850>
web_1  | Traceback (most recent call last):
web_1  |   File "/usr/local/lib/python2.7/site-packages/django/utils/autoreload.py", line 223, in wrapper
web_1  |     fn(*args, **kwargs)
web_1  |   File "/usr/local/lib/python2.7/site-packages/django/core/management/commands/runserver.py", line 112, in inner_run
web_1  |     self.check_migrations()
web_1  |   File "/usr/local/lib/python2.7/site-packages/django/core/management/commands/runserver.py", line 164, in check_migrations
web_1  |     executor = MigrationExecutor(connections[DEFAULT_DB_ALIAS])
web_1  |   File "/usr/local/lib/python2.7/site-packages/django/db/migrations/executor.py", line 19, in __init__
web_1  |     self.loader = MigrationLoader(self.connection)
web_1  |   File "/usr/local/lib/python2.7/site-packages/django/db/migrations/loader.py", line 47, in __init__
web_1  |     self.build_graph()
web_1  |   File "/usr/local/lib/python2.7/site-packages/django/db/migrations/loader.py", line 180, in build_graph
web_1  |     self.applied_migrations = recorder.applied_migrations()
web_1  |   File "/usr/local/lib/python2.7/site-packages/django/db/migrations/recorder.py", line 59, in applied_migrations
web_1  |     self.ensure_schema()
web_1  |   File "/usr/local/lib/python2.7/site-packages/django/db/migrations/recorder.py", line 49, in ensure_schema
web_1  |     if self.Migration._meta.db_table in self.connection.introspection.table_names(self.connection.cursor()):
web_1  |   File "/usr/local/lib/python2.7/site-packages/django/db/backends/base/base.py", line 162, in cursor
web_1  |     cursor = self.make_debug_cursor(self._cursor())
web_1  |   File "/usr/local/lib/python2.7/site-packages/django/db/backends/base/base.py", line 135, in _cursor
web_1  |     self.ensure_connection()
web_1  |   File "/usr/local/lib/python2.7/site-packages/django/db/backends/base/base.py", line 130, in ensure_connection
web_1  |     self.connect()
web_1  |   File "/usr/local/lib/python2.7/site-packages/django/db/utils.py", line 97, in __exit__
web_1  |     six.reraise(dj_exc_type, dj_exc_value, traceback)
web_1  |   File "/usr/local/lib/python2.7/site-packages/django/db/backends/base/base.py", line 130, in ensure_connection
web_1  |     self.connect()
web_1  |   File "/usr/local/lib/python2.7/site-packages/django/db/backends/base/base.py", line 119, in connect
web_1  |     self.connection = self.get_new_connection(conn_params)
web_1  |   File "/usr/local/lib/python2.7/site-packages/django/db/backends/postgresql_psycopg2/base.py", line 172, in get_new_connection
web_1  |     connection = Database.connect(**conn_params)
web_1  |   File "/usr/local/lib/python2.7/site-packages/psycopg2/__init__.py", line 127, in connect
web_1  |     conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
web_1  | django.db.utils.OperationalError: could not connect to server: Connection refused
web_1  |    Is the server running on host "127.0.0.1" and accepting
web_1  |    TCP/IP connections on port 5432?

我错过了什么？

先感谢您