updating readme

Author: gyurisc

README.md

@@ -1,4 +1,25 @@
 # [GramrFixr.com](http://gramrfixr.com)
 
-- Add screenshot / demo 
-- Add description
+This project fixes your grammar using OpenAI GPT-3. 
+
+[![GramrFixr](./public/gramrfixr_screenshot.png)](https://www.gramrfixr.com/)
+
+## How it works 
+
+The project uses the [OpenAI GPT-3 API](https://openai.com/blog/openai-api/) to fix your grammar.
+
+## Running Locally 
+
+After cloning the repo, go to [OpenAI](https://beta.openai.com/) and create an account and put your API key in an .env file. You can create one by renaming .env.example to .env and putting your API key in there. 
+
+Then, run the development server first install the packages:
+
+```bash
+    npm install 
+``` 
+
+and then run the development server:
+
+```bash
+    npm run dev
+```