feat(tmux): improve session creation script

Add a simple README to document it

modules/home-manager/cli/tmux/files/README.md

@@ -0,0 +1,68 @@
+# Create a tmux session
+
+This script help me to create a tmux session and manage related windows, panes and commands.
+
+## Usage
+
+```
+create-tmux-session -n <name> -i <id> -p <project> <command> <command>
+
+-n --name <name>        define a session name
+-i --id <id>            define a session id,
+-r --repo <project>     define the repo used as base directory if not defined
+                        'ghq' and 'fzf' will be use to let you select one
+
+<command>               a command launched in the new created session. you can
+                        use it many time.
+```
+
+## Commands
+
+Commands create windows and panes, launch program and change current directory related to git project (managed by [ghq][ghq]).
+Each command can take a parameter which is mandatpry if no default value exists.
+If parameter contains spaces, must be surrounded by quotes / double quote.
+
+* `vsplit`: split current pane vertically, parameter define the vertical size of the created pane in percent (default 20).
+    ```bash
+    # split first windows, new created pane will take 50% of vertical space
+    create-tmux-session.sh -n mysession vsplit:50
+    ```
+* `hsplit`: split current pane horizontally
+    ```bash
+    # split first windows, new created pane will take 50% of horizontal space
+    create-tmux-session.sh -n mysession hsplit:50
+    ```
+* `neww`: create a new windows, parameter define the new windows name (not mandatory)
+    ```bash
+    # Create a new window name 'shell'
+    create-tmux-session.sh -n mysession -r blog neww:shell
+    ```
+* `run`: launch a command in last created element (window / pane ), parameter define command.
+    ```bash
+    # Just launch ls
+    create-tmux-session.sh -n mysession -r blog run:ls
+
+    # This time with parameters
+    create-tmux-session.sh -n mysession -r blog "run:ls -la"
+    ```
+* `repo`: change current directory to given git repository in parameter.
+    If not parameter is provided, script will launch a menu to select one with `fzf`.
+    New directory will take effect for new created panes / windows after `repo` command.
+    ```bash
+    # change current directory ti ephase:nix repo
+    create-tmux-session.sh -n mysession -r blog repo:ephase/nix neww
+    ```
+
+## Example
+
+Create a new session for my blog repository, launch Neovim, split pane to create a terminal pane bellow text editor then create a new window to lanche development server
+
+```bash
+create-tmux-session.sh -n blog -r ephase/blog 'run:nvim .' vsplit neww 'run:task serve'
+```
+
+Create a new session for my blog like previous example but open new windows with my nix repository and launch Neovim
+
+```bash
+create-tmux-session.sh -n blog -r ephase/blog 'run:nvim .' vsplit neww 'run:task serve' repo:ephase/nix neww:nix 'run:nvim .'
+```