Adding pre-commit and post-checkout hooks

* Pre-commit hook lints JSON
* Post-checkout hook causes hooks directory to update with current
  project hooks
* Readme updated so installation section reminds you to install hooks

README.md

@@ -106,6 +106,7 @@ Example users are in the `vars/secure` directory:
 ```
   mkvirtualenv ansible
   pip install -r ansible-requirements.txt
+  util/sync_hooks.sh
 ```
 
 ### Launching example cloudformation stack - Working example

git-hooks/post-checkout

+#!/bin/sh
+
+echo -n Setting up hooks from git-hooks..
+`pwd`/util/sync_hooks.sh >/dev/null
+if [ $? -eq 0 ]; then
+    echo . done.
+else
+    exit 1
+fi

git-hooks/pre-commit

+#!/bin/sh
+
+echo -n Checking JSON parses..
+`pwd`/util/json_lint.sh
+if [ $? -eq 0 ]; then
+    echo . it does!
+else
+    exit 1
+fi

util/json_lint.sh

+#!/bin/bash
+
+# Do very basic syntax check of every json file to make sure it's valid format
+for file in `find . -iname '*.json'`; do 
+    cat $file | python -m json.tool 1>/dev/null 2>json_complaint.err; 
+    retval=$?
+    if [ $retval != 0 ]; then
+        echo "JSON errors in $file"
+        cat json_complaint.err
+        rm -f json_complaint.err
+        exit $retval;
+    fi
+done
+
+# Everything went ok!
+exit 0

util/sync_hooks.sh

+#!/bin/bash
+
+# Are we running from the git root?
+GITHOOKSFOUND='false'
+if [ -d git-hooks ]; then
+    GITHOOKSFOUND='true';
+fi
+DOTGITHOOKSFOUND='false'
+if [ -d .git -a -d .git/hooks ]; then
+    DOTGITHOOKSFOUND='true';
+fi
+
+# Sync git-hooks directory entries into .git/hooks/
+if [ 'true' = $GITHOOKSFOUND -a 'true' = $DOTGITHOOKSFOUND ]; then
+    for file in git-hooks/*; do
+        filepart=`echo $file | sed -e 's/git-hooks\/\(.*\)/\1/'`
+        if [ -e .git/hooks/$filepart -a ! -L .git/hooks/$filepart ]; then
+            echo ".git/hooks/$filepart not link-managed; bailing..."
+            echo "please examine your .git/hooks/ directory and repair inconsistencies manually"
+            exit 1
+        else
+            ln -v -s -b -f `pwd`/$file -t .git/hooks/
+        fi
+    done
+else
+    echo "Not in git repository root, cannot continue."
+    exit 1
+fi
+
+# Ok, everything went well
+exit 0