🍃 update "development/get_started.mdx"

pages/docs/development/get_started.mdx

@@ -9,6 +9,7 @@ description: Learn how to contribute using GitHub Desktop, VS Code extensions, a
 
 - [Git](https://git-scm.com/downloads) (Essential)
 - [Node.js](https://nodejs.org/en/download) (Essential, use the LTS version)
+- [MongoDB](https://www.mongodb.com/try/download/community) (Essential, for the database)
 - [Git LFS](https://git-lfs.com/) (Useful for larger files)
 - [GitHub Desktop](https://desktop.github.com/) (Optional)
 - [VSCode](https://code.visualstudio.com/Download) (Recommended Source-code Editor)
@@ -71,6 +72,7 @@ git clone -b branch-name https://github.com/username/LibreChat.git
 
 <Callout type="warning" title="Warning">
   The default values in `.env.example` are usually fine, except for `MONGO_URI`. Provide your own.
+  Make sure to install MongoDB and configure `MONGO_URI` correctly to connect to your MongoDB instance.
   Use [MongoDB Community Server](https://www.mongodb.com/try/download/community) or [MongoDB Atlas
   Cloud](https://www.mongodb.com/cloud/atlas/register).
 </Callout>