Adding build script

It is not possible to publish the node_modules directory => building to js instead of ts-node and typescript peer dependency requirement

.gitignore

@@ -1 +1,2 @@
 node_modules
+**/*.js

.npmignore

@@ -0,0 +1,2 @@
+package-lock.json
+**/*.ts

package.json

@@ -8,6 +8,7 @@
   },
   "scripts": {
     "start": "ts-node dependency-tree.ts",
+    "build": "tsc",
     "test": "echo \"Error: no test specified\" && exit 1"
   },
   "author": "",