README.md in flexdot-3.2.0 vs README.md in flexdot-3.3.0

@@ -7,11 +7,11 @@
 
 ## Getting Started
 
 ### Prerequisite
 
-Ruby 2.6+
+Ruby 2.7+
 
 ### Installing
 
 Create the following directory structure:
 
@@ -51,10 +51,16 @@
 
   # (optional)
   # Whether or not to colorize the output
   # Default: true
   output_colorize: true
+
+  # (optional)
+  # Whether to automatically delete old backups.
+  # If nil, do not delete, otherwise keep to the specified number of backups.
+  # Default: nil
+  keep_max_backup_count: 10
 )
 ```
 
 It is recommended that you add the Rakefile to `gitignore`:
 
@@ -66,191 +72,12 @@
 Finally, run `rake -T` in the `$HOME/dotfiles` and make sure that the output is as follows:
 
     $ rake -T
     rake clear_backups
 
-## Example
+## Usage
 
-This example is my actual dotfile environment.
-
-I have two working environments, macOS and ubuntu. The dotfiles in these environments are slightly different, so each dotfile is separated.
-
-### Directory Structure
-
-```
-$HOME/dotfiles
-├── common
-│   ├── bin
-│   │   ├── git-delete-other-branches
-│   │   └── git-reset-and-clean
-│   ├── git
-│   │   └── ignore
-│   ├── rubygems
-│   │   └── .gemrc
-│   └── vim
-│       └── .vimrc
-├── macOS
-│   ├── bash
-│   │   ├── .bash_profile
-│   │   └── .bashrc
-│   ├── git
-│   │   └── .gitconfig
-│   ├── karabiner
-│   │   └── tab-emulation.json
-│   └── vscode
-│       ├── keybindings.json
-│       └── settings.json
-├── ubuntu
-│   ├── bash
-│   │   └── .bashrc
-│   ├── bin
-│   │   ├── upgrade-ghcli
-│   │   ├── utils
-│   │   ├── x-copy
-│   │   └── x-open
-│   ├── git
-│   │   └── .gitconfig
-│   ├── vscode
-│   │   ├── keybindings.json
-│   │   └── settings.json
-│   └── xkeysnail
-│       ├── config.py
-│       ├── debug.sh
-│       ├── restart.sh
-│       ├── start.sh
-│       └── stop.sh
-├── macOS.yml
-├── ubuntu.yml
-└── Rakefile
-```
-
-### Rakefile
-
-```ruby
-require 'flexdot'
-
-Flexdot.setup(
-  home_dir: '..'
-)
-
-# You can execute `install:macOS` when you run `rake` command
-# with no arguments by defining it as follows:
-task default: 'install:macOS'
-```
-
-### Available Commands
-
-When you run the `rake -T` command in that directory structure, you should have two installation commands available:
-
-    $ rake -T
-    rake clear_backups   # Clear all backups
-    rake install:macOS   # Install dotfiles for macOS
-    rake install:ubuntu  # Install dotfiles for ubuntu
-
-### Dotfile Index File
-
-`macOS.yml` and `ubuntu.yml` are for setting the link destination of dotfile. dotfile will be installed according to its setting.
-
-#### macOS.yml
-
-For example, `common -> bin -> git-delete-other-branchs` is `$HOME/dotfiles/common/bin/git-delete-other-branches`.
-And the value `bin` means `$HOME/bin` directory.
-
-So this defines linking `$HOME/dotfiles/common/bin/git-delete-other-branches` to `$HOME/bin/git-delete-other-branches`.
-
-
-```yml
-common:
-  bin:
-    git-delete-other-branches: bin
-    git-reset-and-clean: bin
-  git:
-    ignore: .config/git
-  rubygems:
-    .gemrc: .
-  vim:
-    .vimrc: .
-
-macOS:
-  bash:
-    .bash_profile: .
-    .bashrc: .
-  git:
-    .gitconfig: .
-  karabiner:
-    tab-emulation.json: .config/karabiner/assets/complex_modifications
-  vscode:
-    keybindings.json: Library/Application Support/Code/User
-    settings.json: Library/Application Support/Code/User
-```
-
-#### ubuntu.yml
-
-```yml
-common:
-  bin:
-    git-delete-other-branchs: bin
-    git-reset-and-clean: bin
-  git:
-    ignore: .config/git
-  rubygems:
-    .gemrc: .
-  vim:
-    .vimrc: .
-
-ubuntu:
-  bash:
-    .bashrc: .
-  bin:
-    upgrade-ghcli: bin
-    utils: bin
-    x-copy: bin
-    x-open: bin
-  git:
-    .gitconfig: .
-  vscode:
-    keybindings.json: .config/Code/User
-    settings.json: .config/Code/User
-  xkeysnail:
-    config.py: .xkeysnail
-    debug.sh: .xkeysnail
-    restart.sh: .xkeysnail
-    start.sh: .xkeysnail
-    stop.sh: .xkeysnail
-```
-
-### Installing dotfiles for macOS
-
-    $ rake
-
-Or,
-
-    $ rake install:macOS
-
-The following is the output result:
-
-```
-already linked: bin/git-delete-other-branches
-already linked: bin/git-reset-and-clean
-already linked: .config/git/ignore
-already linked: .gemrc
-already linked: .vimrc
-link created: .bash_profile (backup)
-link created: .bashrc (backup)
-link created: .gitconfig (backup)
-link created: .config/karabiner/assets/complex_modifications/tab-emulation.json (backup)
-link created: Library/Application Support/Code/User/keybindings.json (backup)
-link created: Library/Application Support/Code/User/settings.json (backup)
-```
-
-`already_linked` means skipped because `bin/git-delete-other-branches` is already linked. `link_created` means the link was created.
-Also, `(backup)` means that a file exists in the link path and that file was backed up to `$HOME/dotfiles/backup/YYYYMMDDHHIISS/filename`.
-
-### Misc
-
-You can clear all backups in `$HOME/dotfiles/backup/YYYYMMDDHHIISS` to run `rake clear_backups`.
-
-    $ rake clear_backups
+See [doc/example.md](doc/example.md)
 
 ## License
 
 The gem is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).