Create a file dev.secret.exs and test.secret.exs into config folder. The dummy file:
use Mix.Config
config :grapevine, Grapevine.Repo,
  username: "postgres",
  password: "postgres",
  database: "grapevine_dev",
  hostname: "localhost",
  show_sensitive_data_on_connection_error: true,
  pool_size: 10And update the values for username, password, hostname.
Setup the project with mix setup.
Start Phoenix endpoint with mix phx.server.
Now you can visit localhost:4000 from your browser.
Add instructions into priv/repo/seeds.exs to delete dummy users and posts and create all dummy users and posts, when its run mix run priv/repo/seeds.exs or mix setup.
| password | |
|---|---|
| [email protected] | passwordpass | 
| [email protected] | passwordpass |