Fix env variables for dev setup (twentyhq#1031)

Author: emilienchvt

server/.env.example

@@ -1,5 +1,5 @@
-PG_DATABASE_URL=postgres://postgres:postgrespassword@localhost:5432/default?connection_limit=1
-FRONT_BASE_URL=http://localhost:3001
+PG_DATABASE_URL=postgres://postgres:postgrespassword@postgres:5432/default?connection_limit=1
+FRONT_BASE_URL=http://localhost:3000
 ACCESS_TOKEN_SECRET=replace_me_with_a_random_string
 LOGIN_TOKEN_SECRET=replace_me_with_a_random_string
 REFRESH_TOKEN_SECRET=replace_me_with_a_random_string