force an npm rebuild to work around issue #129, missing bcrypt bindings file

see https://github.com/npm/npm/issues/5400

Gruntfile.coffee

@@ -152,6 +152,8 @@ module.exports = (grunt) ->
 			Helpers.cloneGitRepo service, (error) ->
 				return callback(error) if error?
 				Helpers.installNpmModules service, (error) ->
+					return callback(error) if error?
+					Helpers.rebuildNpmModules service, (error) ->
 						return callback(error) if error?
 						Helpers.runGruntInstall service, (error) ->
 							return callback(error) if error?
@@ -161,6 +163,8 @@ module.exports = (grunt) ->
 			Helpers.updateGitRepo service, (error) ->
 				return callback(error) if error?
 				Helpers.installNpmModules service, (error) ->
+					return callback(error) if error?
+					Helpers.rebuildNpmModules service, (error) ->
 						return callback(error) if error?
 						Helpers.runGruntInstall service, (error) ->
 							return callback(error) if error?
@@ -214,6 +218,14 @@ module.exports = (grunt) ->
 			proc.on "close", () ->
 				callback()
 
+		# work around for https://github.com/npm/npm/issues/5400
+		# where binary modules are not built due to bug in npm
+		rebuildNpmModules: (service, callback = (error) ->) ->
+			dir = service.name
+			proc = spawn "npm", ["rebuild"], stdio: "inherit", cwd: dir
+			proc.on "close", () ->
+				callback()
+
 		createDataDirs: (callback = (error) ->) ->
 			DIRS = [
 				"tmp/dumpFolder"