Add gulp build file for creating combined contao leaflet

gulpfile.js

@@ -0,0 +1,23 @@
+var gulp       = require('gulp');
+var del        = require('del');
+var sourcemaps = require('gulp-sourcemaps');
+var rename     = require('gulp-rename');
+var uglify     = require('gulp-uglify');
+var concat     = require('gulp-concat');
+
+var paths = {
+    minified: 'contao-leaflet.js',
+    scripts:  ['assets/maps/src/*.js'],
+    dest:     'assets/maps'
+};
+
+gulp.task('clear', function(cb) {
+    del([paths.dest + '/' + paths.minified], cb);
+});
+
+gulp.task('scripts', ['clear'], function() {
+    return gulp.src(paths.scripts)
+        .pipe(concat(paths.minified))
+        .pipe(uglify())
+        .pipe(gulp.dest(paths.dest));
+});