[GRASS-git] [OSGeo/grass-website] 11fd95: add developer manuals (#8)

[Stefan Blumentrath]

  Branch: refs/heads/master
  Home:   https://github.com/OSGeo/grass-website
  Commit: 11fd9503f983345cabc1b1400639a5d83a797ee2
      https://github.com/OSGeo/grass-website/commit/11fd9503f983345cabc1b1400639a5d83a797ee2
  Author: Stefan Blumentrath <stefan.blumentrath at gmx.de>
  Date:   2020-02-15 (Sat, 15 Feb 2020)

  Changed paths:
    M content/learn/manuals.md

  Log Message:
  -----------
  add developer manuals (#8)

Co-authored-by: Markus Neteler <neteler at gmail.com>