Added descriptive error if run outside of a git repository

Author: HalfVoxel

lib/git-media.rb

@@ -123,6 +123,10 @@ def self.get_pull_transport
  module Application
  def self.run!
 
+ if !system('git rev-parse')
+ return
+ end
+ 
  cmd = ARGV.shift # get the subcommand
  cmd_opts = case cmd
  when "filter-clean" # parse delete options