[docs] moved tmux doc to docs folder

docs/setup/setup.tmux.md

@@ -0,0 +1,37 @@
+# tmux
+
+## create new tmux session
+```shell
+tuxifier new-session default
+```
+
+## add following script
+```shell
+if initialize_session "default"; then
+
+  # open dotfiles
+  new_window "dotfiles"
+  run_cmd "cd ~/.dotfiles"
+  run_cmd "nvim"
+
+  # open siempie
+  new_window "siempie"
+  run_cmd "cd ~/Documents/git/siempie"
+  run_cmd "nvim"
+
+  # open itcreation
+  new_window "itcreation"
+  run_cmd "cd ~/Documents/git/itcreation"
+  run_cmd "nvim"
+
+  # open empty shell
+  new_window "simon"
+
+  # go by default to the open shell
+  select_window 4
+
+fi
+
+# finalize session creation and switch/attach to it.
+finalize_and_go_to_session
+```