add gitlab-ci.yml and update .gitignore

2 jobs for main in 5 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
failed #69803
linux
go_test

00:00:05

 
  Build
skipped #69804
linux
go_build
 
Name Stage Failure
failed
go_test Test
Checking out 54d86baf as main...

Skipping Git submodules setup
Executing "step_script" stage of the job script
Using docker image sha256:a13cfbac519cc80093523bb263f994859ab87f528558ed1148636e9268c30f60 for git-registry.mycard.moe/mycard/docker-runner-base:master-x86 with digest git-registry.mycard.moe/mycard/docker-runner-base@sha256:ad6bdae65540a7ff0a0fa89101663847f0457014c9e397b583329fed81c9c638 ...
$ go test
/bin/bash: line 107: go: command not found
Cleaning up file based variables
ERROR: Job failed: exit code 1