Add RuboCop git hook

[#155618738](https://www.pivotaltracker.com/story/show/155618738)

Co-authored-by: Sebastian Heid <sebastian.heid@sap.com>

git-hooks/pre-commit

@@ -0,0 +1,2 @@
+unset GIT_DIR
+scripts/rubocop-staged

scripts/install-git-hooks

@@ -0,0 +1,17 @@
+#!/bin/bash
+
+ROOT_DIR=$(cd $(dirname $0)/.. && pwd)
+PRE_COMMIT=${ROOT_DIR}/.git/hooks/pre-commit
+
+if [ ! -f ${PRE_COMMIT} ]; then
+  echo "#!/bin/bash" > ${PRE_COMMIT}
+  chmod +x ${PRE_COMMIT}
+fi
+
+if grep -q 'git-hooks/pre-commit' ${PRE_COMMIT}; then
+  echo "pre-commit already installed."
+else
+  echo >> ${PRE_COMMIT}
+  echo './git-hooks/pre-commit' >> ${PRE_COMMIT}
+  echo "pre-commit installed."
+fi

scripts/rubocop-staged

@@ -0,0 +1,12 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require 'English'
+
+Dir.chdir(File.expand_path(__dir__ + '/../src/bosh_openstack_cpi')) do
+  command = 'bundle exec rubocop-git --cached'
+  puts("Running '#{command}'")
+  system(command)
+end
+
+exit $CHILD_STATUS.exitstatus

scripts/test-unit

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+"$(dirname $0)/install-git-hooks"
+
+pushd "$(dirname $0)/../src/bosh_openstack_cpi"
+  bundle install
+  bundle exec rspec spec/unit
+popd

src/bosh_openstack_cpi/Gemfile

@@ -13,6 +13,8 @@ group :development, :test do
   gem 'rake', '~>10.3.2'
   gem 'rspec', '~> 3.3.0'
   gem 'rspec-its', '~> 1.0.1'
+  gem 'rubocop'
+  gem 'rubocop-git'
   gem 'timecop', '~>0.7.1'
   gem 'webmock', '~>2.3.2'
 end

src/bosh_openstack_cpi/Gemfile.lock

@@ -3,6 +3,7 @@ GEM
   specs:
     addressable (2.5.2)
       public_suffix (>= 2.0.2, < 4.0)
+    ast (2.4.0)
     bosh_common (1.3262.24.0)
       logging (~> 1.8.2)
       semi_semantic (~> 1.2.0)
@@ -38,7 +39,12 @@ GEM
     minitar (0.5.4)
     multi_json (1.13.1)
     netaddr (1.5.1)
+    parallel (1.12.1)
+    parser (2.5.0.4)
+      ast (~> 2.4.0)
+    powerpack (0.1.1)
     public_suffix (3.0.2)
+    rainbow (3.0.0)
     rake (10.3.2)
     rspec (3.3.0)
       rspec-core (~> 3.3.0)
@@ -56,9 +62,20 @@ GEM
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.3.0)
     rspec-support (3.3.0)
+    rubocop (0.54.0)
+      parallel (~> 1.10)
+      parser (>= 2.5)
+      powerpack (~> 0.1)
+      rainbow (>= 2.2.2, < 4.0)
+      ruby-progressbar (~> 1.7)
+      unicode-display_width (~> 1.0, >= 1.0.1)
+    rubocop-git (0.1.3)
+      rubocop (>= 0.24.1)
+    ruby-progressbar (1.9.0)
     safe_yaml (1.0.4)
     semi_semantic (1.2.0)
     timecop (0.7.4)
+    unicode-display_width (1.3.0)
     webmock (2.3.2)
       addressable (>= 2.3.6)
       crack (>= 0.3.2)
@@ -79,8 +96,10 @@ DEPENDENCIES
   rake (~> 10.3.2)
   rspec (~> 3.3.0)
   rspec-its (~> 1.0.1)
+  rubocop
+  rubocop-git
   timecop (~> 0.7.1)
   webmock (~> 2.3.2)
 
 BUNDLED WITH
-   1.16.0
+   1.16.1