[Emacs] add Docker Tramp method, move yadm Tramp method

This commit adds the connection method for Docker containers through
Tramp and stores it under the newly created Tramp heading under which
the implementation of the Yadm connection method is implemented.

org/config/emacs.org

@@ -3908,13 +3908,56 @@
       \{\{\{nyqy($1)\}\}\} $0
     #+END_SRC
 
-** Yadm
+** Tramp configuration
+   :PROPERTIES:
+   :CUSTOM_ID: User_Configuration-Tramp_configuration-acb4733b
+   :END:
+*** Docker
+    :PROPERTIES:
+    :CUSTOM_ID: User_Configuration-Tramp_configuration-Docker-31573fdf
+    :END:
+    It is  completely possible with Tramp  to connect ot a  docker container and
+    modify files inside of  it. It is not supported natively, but  we can add it
+    quite easily. Be aware,  I am not the author of this code,  you can find its
+    original source [[https://www.emacswiki.org/emacs/TrampAndDocker][here]]. First, let’s add the Docker protocol to Tramp:
+    #+BEGIN_SRC emacs-lisp
+      (push
+       (cons
+        "docker"
+        '((tramp-login-program "docker")
+          (tramp-login-args (("exec" "-it") ("%h") ("/bin/bash")))
+          (tramp-remote-shell "/bin/sh")
+          (tramp-remote-shell-args ("-i") ("-c"))))
+       tramp-methods)
+    #+END_SRC
+
+    Now that the  method has been added, let’s add  some autocompletion for when
+    we want to connect to a Docker container:
+    #+BEGIN_SRC emacs-lisp
+      (defadvice tramp-completion-handle-file-name-all-completions
+          (around dotemacs-completion-docker activate)
+        "(tramp-completion-handle-file-name-all-completions \"\" \"/docker:\" returns
+          a list of active Docker container names, followed by colons."
+        (if (equal (ad-get-arg 1) "/docker:")
+            (let* ((dockernames-raw (shell-command-to-string "docker ps --format '{{.Names}}:'"))
+                   (dockernames (cl-remove-if-not #'(lambda (dockerline)
+                                                      (string-match ":$" dockerline))
+                                                  (split-string dockernames-raw "\n"))))
+              (setq ad-return-value dockernames))
+          ad-do-it))
+    #+END_SRC
+
+    And that’s  it! it  is now possible  to connect to  a docker  container with
+    something   like ~/docker:conlangdict_server/~   as  the   path  given   in
+ ~find-file~.
+
+*** Yadm
    :PROPERTIES:
    :CUSTOM_ID: User_Configuration-Yadm-4344fec3
    :END:
-   yadm is  the utility  I use  for managing my  dotfiles, and  it is  a wrapper
+ ~yadm~ is the utility I use for managing  my dotfiles, and it is a wrapper In
-   In order to manage my dotfiles, I use the following shortcut to launch Magit
+   order to  manage my dotfiles,  I use the  following shortcut to  launch Magit
-   Status for yadm:
+   Status for ~yadm~:
    #+BEGIN_SRC emacs-lisp
      (spacemacs/declare-prefix "oy" "yadm status")
      (spacemacs/set-leader-keys "oy" (lambda () (interactive) (magit-status "/yadm::")))