doc: add docs about using MPI in docker. (#4060)

* add docs.

* Update docs/community/faq.md

Co-authored-by: Chun Cai <amoycaic@gmail.com>

* Update docs/community/faq.md

Co-authored-by: Chun Cai <amoycaic@gmail.com>

---------

Co-authored-by: Chun Cai <amoycaic@gmail.com>

Author: grysgreat

docs/community/faq.md

@@ -80,6 +80,8 @@ If the program prompt something like "KILLED BY SIGNAL: 9 (Killed)", it may be c
 
 If the error message is "Segmentation fault", or there is no enough information on the error, please feel free to submit an issue.
 
+**4. Error "Read -1" when using mpirun in docker environment**
+This is a [known issue](https://github.com/open-mpi/ompi/issues/4948) of OpenMPI running in a docker container. In this case, please set environment variable `OMPI_MCA_btl_vader_single_copy_mechanism=none`.
 ## Miscellaneous
 
 **1. How to visualize charge density file?**