Create local_compile.md

[photocyte]

Not familiar with the typical Go compile process, but the procedure added in local_compile.md worked for me whereas the current instructions did not work. Haven't checked if the actual binary fails to work or not yet! But at least it shows the cas dialog:

Content Addressable Storage

Usage:
  cas [command]

Available Commands:
  blob        commands related to the binary data in content-addressable storage
  checkout    restore a pin or hash to a specified path
  completion  Generate the autocompletion script for the specified shell
  fetch       store the URL or file in the content-addressable storage
  hash        hash files
  help        Help about any command
  http        commands related to HTTP protocol
  init        init content-addressable storage in current directory
  pin         set a named pin pointing to a ref
  pipeline    process blobs via a pipeline
  proxy       proxy http requests and save them to CAS
  pull        store the URL or file in the content-addressable storage under a named pin
  schema      commands related to the CAS schema
  serve       serve CAS over HTTP
  sync        syncs one or more remote blobs

Flags:
  -h, --help   help for cas

Use "cas [command] --help" for more information about a command.

[dennwc]

Sorry for the bitrot of the documentation. I updated the build instructions for new Go version. It's easier than the steps proposed here, so I'm closing this PR. Thank you for reaching out!