put virtualenv activation during build in comment. That means that for the moment the build machine must be provisionned beforehand, or ansible must be available globally
{
"private": true,
"devDependencies": {
"bower": "^1.5.3",
"gulp": "^3.8.8",
"gulp-exec": "^2.1.2",
"minimist": "^1.2.0",
"run-sequence": "^1.2.2"
},
"dependencies": {
"laravel-elixir": "^4.0.0",
"bootstrap-sass": "^3.0.0"
}
}