Butler 9 merge override variables (#29)

* BUTLER-9 #time 2.5h: Merge default settings with an overrides object.

* BUTLER-9 #time 10m: Forgot to uncomment something.

Gulpfile.js

@@ -15,10 +15,17 @@ var defaults = require('./config/butler.defaults.js');
 
 // Add local config on top; this file should not define an empty defaults var.
 try {
-  var defaults = require('../../conf/butler.defaults.js');
+  var overrides = require('../../conf/butler.defaults.js');
+  defaults = extend(defaults, overrides);
 }
 catch (e) {}
 
+// Helper function to merge to js objects.
+function extend(obj, src) {
+  Object.keys(src).forEach(function(key) { obj[key] = src[key]; });
+  return obj;
+}
+
 // Just run linters
 gulp.task('lint', function() {
   console.log('Running linters...');

config/butler.config.sh

@@ -2,11 +2,12 @@
 
 if [ ! -e ../../conf/butler.defaults.js ]; then
   echo "// Project-specific Butler configuration." > ../../conf/butler.defaults.js
+  echo "var overrides = {};" >> ../../conf/butler.defaults.js
   echo "" >> ../../conf/butler.defaults.js
 
   echo "Please provide the repository link for this project. Eg: https://github.com/palantirnet/butler.git"
   read project_repo
-  echo "defaults.repo = \"$project_repo\";" >> ../../conf/butler.defaults.js
+  echo "overrides.repo = \"$project_repo\";" >> ../../conf/butler.defaults.js
 fi;
 
 echo "Thanks for using Butler!"