feat: add dotenv library for environment variables usage

Author: Victor

package.json

@@ -4,6 +4,7 @@
   "main": "index.js",
   "license": "MIT",
   "dependencies": {
+    "dotenv": "^10.0.0",
     "express": "^4.17.2"
   },
   "devDependencies": {

yarn.lock

@@ -1044,6 +1044,11 @@ detect-indent@^4.0.0:
   dependencies:
     repeating "^2.0.0"
 
+dotenv@^10.0.0:
+  version "10.0.0"
+  resolved "https://registry.yarnpkg.com/dotenv/-/dotenv-10.0.0.tgz#3d4227b8fb95f81096cdd2b66653fb2c7085ba81"
+  integrity sha512-rlBi9d8jpv9Sf1klPjNfFAuWDjKLwTIJJ/VxtoTwIR6hnZxcEOQCZg2oIL3MWBYw5GpUDKOEnND7LXTbIpQ03Q==
+
 ee-first@1.1.1:
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/ee-first/-/ee-first-1.1.1.tgz#590c61156b0ae2f4f0255732a158b266bc56b21d"