fix: if PUBLIC_URL setted, static resources cannot be fetched from the backend.

[liuyuanzhi-cn]

Bug Reproduction Steps

1. Modify the PUBLIC_URL in the ui/.env.production file:

  TSC_COMPILE_ON_ERROR=true
  ESLINT_NO_DEV_ERRORS=true
  PUBLIC_URL = /forum
  REACT_APP_API_URL = /

2. Recompile

  make ui
  make build

3. Execute the initialization command:

INSTALL_PORT=9080 ./answer init -C ./answer-data/

4. Access the initialization configuration page at http://localhost:9080/install and encounter the following error.

Bug Resolution

During initialization and runtime, it is necessary to add the environment variable PUBLIC_URL.

# Initialization
INSTALL_PORT=9080 PUBLIC_URL=/forum ./answer init -C ./answer-data/
# Run
PUBLIC_URL=/forum ./answer run -C ./answer-data/

Note：

1. If the value of PUBLIC_URL is the default /, there is no need to set the environment variable.
2. The value of PUBLIC_URL must not end with /. For example, PUBLIC_URL=/forum is correct, while PUBLIC_URL=/forum/ is incorrect.