chore: insert a .env.example file to faciliate development experience

This commit introduces the `.env.example` file with the necessary named
environment variables to be filled so the project as a whole may start
up with the necessary secret information.

Author: mrlemoos

.env.example

@@ -0,0 +1,21 @@
+# Next.js environment variables
+NEXT_PUBLIC_VERCEL_URL=http://localhost:3000
+
+# Database environment variables
+DATABASE_URL=postgresql://postgres:docker@localhost:5432/louffee
+DIRECT_DATABASE_URL=postgresql://postgres:docker@localhost:5432/louffee
+
+# Cloudflare environment variables
+CLOUDFLARE_ACCOUNT_ID="<account_id>"
+CLOUDFLARE_ACCESS_KEY="<access_key>"
+CLOUDFLARE_SECRET_KEY="<secret_key>"
+
+CLOUDFLARE_UPLOAD_BUCKET_ID="<bucket_id>"
+CLOUDFLARE_UPLOAD_BUCKET_NAME="louffee-dev-upload"
+CLOUDFLARE_STORAGE_BUCKET_NAME="louffee-dev"
+
+# Next Auth environment variables
+NEXTAUTH_URL="http://localhost:3000"
+NEXTAUTH_SECRET="<secret>"
+GOOGLE_CLIENT_ID="<google_client_id>"
+GOOGLE_CLIENT_SECRET="<google_client_secret>"