Add rubocop binstub that rspects file patterns

Best of both worlds!

(Because you can't override the default rubocop includes)

The binstub basically, lets me safely `rubocop test/foo_test.rb`
instead of `bundle exec rubocop test/foo_test.rb`

```bash
  # ~/.profile
  # https://twitter.com/tpope/status/165631968996900865
  # tl;dr `mkdir .git/safe` to add `bin` to path, e.g. `bin/rails`
  PATH=".git/safe/../../bin:$PATH"
```

bin/rubocop

@@ -0,0 +1,38 @@
+#!/usr/bin/env bash
+#
+# Usage:
+#   bin/rubocop [-A|-t|-h]
+#   bin/rubocop [file or path] [cli options]
+#
+# Options:
+#  Autocorrect    -A
+#  AutoGenConfig  -t
+#  Usage          -h,--help,help
+
+set -e
+
+case $1 in
+  -A)
+     echo "Rubocop autocorrect is ON" >&2
+     bundle exec rake -f lib/tasks/rubocop.rake rubocop:auto_correct
+     ;;
+
+  -t)
+     echo "Rubocop is generating a new TODO" >&2
+     bundle exec rake -f lib/tasks/rubocop.rake rubocop:auto_gen_config
+     ;;
+
+  -h|--help|help)
+     sed -ne '/^#/!q;s/.\{1,2\}//;1d;p' < "$0"
+     ;;
+
+  *)
+     # with no args, run vanilla rubocop
+     # else assume we're passing in arbitrary arguments
+     if [ -z "$1" ]; then
+       bundle exec rake -f lib/tasks/rubocop.rake rubocop
+     else
+       bundle exec rubocop "$@"
+     fi
+     ;;
+esac