[CI] Add CI script, add export script

Drone script calls new `export.el' script written in Emacs Lisp to
export all org files to HTML files.

HTML files should then be uploaded to a remote server with SCP

.drone.yml

@@ -0,0 +1,35 @@
+kind: pipeline
+name: default
+
+steps:
+- name: build
+  image: silex/emacs:27
+  commands:
+    - pwd
+    - ls -ahl
+    - which emacs
+    - emacs --script export.el
+
+- name: deploy
+  image: appleboy/drone-scp
+  settings:
+    host:
+      from_secret: ssh_host
+    target:
+      from_secret: ssh_target
+    source:
+      - !org/config/LICENSE.md
+      - org/config/*.html
+    strip_components: 2
+    username:
+      from_secret: ssh_username
+    password:
+      from_secret: ssh_password
+    port:
+      from_secret: ssh_port
+  # when:
+  #   branch:
+  #   - master
+  #   event:
+  #     exclude:
+  #     - pull_request

export.el

@@ -0,0 +1,21 @@
+#!/usr/bin/emacs --script
+(require 'package)
+(add-to-list 'package-archives '("melpa" . "https://melpa.org/packages/") t)
+(package-initialize)
+(package-refresh-contents)
+(package-install 'htmlize)
+(package-install 's)
+(require 's)
+(setq org-confirm-babel-evaluate nil)
+(let* ((files (mapcar #'expand-file-name
+                      (file-expand-wildcards "org/config/*.org"))))
+  (mapc (lambda (file)
+          (message (format "==========\nExporting %S\n==========" file))
+          (with-current-buffer (find-file file)
+            (org-html-export-to-html)))
+        files))
+(let* ((files (mapcar #'expand-file-name
+                      (file-expand-wildcards "org/config/*.html~"))))
+  (mapc (lambda (file)
+          (delete-file file))
+        files))