doc: add explanations for each command

package.json

@@ -8,6 +8,14 @@
     "move_static": "cp -R static/ build/",
     "test": "mocha -r ts-node/register test/**/*.spec.ts"
   },
+  "scriptsComments": {
+    "archive": "Runs [test], [clean_build], [build], [move_static] and finally [zip_build]",
+    "zip_build": "Package all files in the build/ folder to a single zip file. Uses to publish the extension on the Chrome Web Store https://chrome.google.com/webstore/detail/otto-tabs/pjgajilkdijnbfmglfbpnenocpajmdlb",
+    "build": "Compile all typescript files according to the tsconfig.json configuration file",
+    "clean_build": "Remove all files in the build/ folder",
+    "move_static": "Copy all static files from static/ to build/ folder",
+    "test": "Runs all tests located in the test/ folder"
+  },
   "devDependencies": {
     "@types/chai": "^4.1.6",
     "@types/chai-spies": "^1.0.0",