Added .env in gitignore; README warns not to commit real secrets (#10)

Author: fynd-kevinrajgor

.gitignore

@@ -2,4 +2,9 @@
 node_modules
 /public/dist
 # ignore coverage
-coverage/
+coverage/
+
+# local env files
+.env.local
+.env.*.local
+.env

README.md

@@ -32,3 +32,5 @@ Below is the structure of the project directory along with brief descriptions of
 [coveralls-badge]: https://coveralls.io/repos/github/gofynd/example-extension-vue/badge.svg?branch=main&&kill_cache=1
 [coveralls-url]: https://coveralls.io/github/gofynd/example-extension-vue?branch=main
 
+## Environment Variables
+- Never commit `.env` or any file that contains real environment variables and secrets; use `.env.example` (with placeholder values only) for documentation in the repository.