improved README

added haskell stack installation on README.md

README.md

@@ -44,25 +44,27 @@ algorithm, by theory, every match is either draw or the bot is the winner.
     git clone https://gitlab.cs.ui.ac.id/pemfung-fun/tic-tac-toe.git
     ```
 
-2. Install [aws-sam-cli](https://pypi.org/project/aws-sam-cli/)
+2. Install [haskell stack](https://github.com/commercialhaskell/stack/tree/master/doc)
+
+3. Install [aws-sam-cli](https://pypi.org/project/aws-sam-cli/)
 
     ```shell
     pip install aws-sam-cli
     ```
 
-3. Build the project
+4. Build the project
 
     ```shell
     make
     ```
 
-4. Unzip `build/function.zip` and move to project's root folder
+5. Unzip `build/function.zip` and move to project's root folder
 
     ```shell
     unzip build/function.zip
     ```
 
-5. Run this [FaaS](https://en.wikipedia.org/wiki/Function_as_a_service) locally
+6. Run this [FaaS](https://en.wikipedia.org/wiki/Function_as_a_service) locally
 
     ```shell
     sam local start-api --host 127.0.0.1 --port 3000
@@ -71,7 +73,7 @@ algorithm, by theory, every match is either draw or the bot is the winner.
     > see [the docs](https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-cli-command-reference-sam-local-start-api.html)
     for more options.
 
-6. Now you can try to POST something like this
+7. Now you can try to POST something like this
 
     ```shell
     curl -v\