Tightened up git checking to check for a minimum installed version of

Git.

lib/homesick.rb

@@ -8,6 +8,7 @@ require 'homesick/cli'
 # Homesick's top-level module
 module Homesick
   GITHUB_NAME_REPO_PATTERN = /\A([A-Za-z0-9_-]+\/[A-Za-z0-9_-]+)\Z/
+  GIT_VERSION_PATTERN = /[#{Homesick::Actions::GitActions::MAJOR}-9]\.[#{Homesick::Actions::GitActions::MINOR}-9]\.[#{Homesick::Actions::GitActions::PATCH}-9]/
   SUBDIR_FILENAME = '.homesick_subdir'
 
   DEFAULT_CASTLE_NAME = 'dotfiles'

lib/homesick/actions/git_actions.rb

@@ -3,6 +3,12 @@ module Homesick
   module Actions
     # Git-related helper methods for Homesick
     module GitActions
+      # Information on the minimum git version required for Homesick
+      MAJOR = 2
+      MINOR = 0
+      PATCH = 0
+      STRING = [MAJOR, MINOR, PATCH].compact.join('.')
+
       # TODO: move this to be more like thor's template, empty_directory, etc
       def git_clone(repo, config = {})
         config ||= {}

lib/homesick/cli.rb

@@ -20,8 +20,8 @@ module Homesick
     def initialize(args = [], options = {}, config = {})
       super
       # Check if git is installed
-      unless `git --version`.size > 0
-        say_status :error, 'Git must be installed to use Homesick', :red
+      unless `git --version` =~ GIT_VERSION_PATTERN
+        say_status :error, "Git version >= #{Homesick::Actions::GitActions::STRING} must be installed to use Homesick", :red
         exit(1)
       end
       # Hack in support for diffing symlinks