Update README

Author: ciaransweet

README.md

@@ -1,2 +1,59 @@
-# localstack_and_lambda_layers
-An example on how to implement Lambda Layers within the free LocalStack offering
+# Lambda Layers in LocalStack (The free version)
+
+*Using the free version of LocalStack? Need to use Lambda Layers? Look no further!*
+
+## Prequisites
+* Python 3+
+* Docker Compose
+
+Install the required pip packages for the project with:
+```
+$ pip3 install -r requirements.txt
+```
+
+# Run LocalStack
+
+Run the LocalStack container in the background with:
+```
+$ docker-compose up -d
+# If you're a MacOS user like me, you might need to do:
+$ mkdir lstmp
+$ TMPDIR=./lstmp docker-compose up -d
+```
+
+After a while it will be ready, you can double check this by seeing if `Ready.` is in the logs:
+```
+$ docker logs -f localstack
+...
+...
+Ready.
+```
+
+# Create the Layer, deploy the Lambda and test it:
+
+```
+$ cd lambda
+$ bash test-lambda.sh
+Build Layer and extract zip of dependencies
+ac038acb524c360a5b8a4e47277abea58919e4ad2eaee33aed7c2b6c44b2fd92
+-----------------------
+Creating lambda layer
+-----------------------
+Remove lambda python packages
+Remove useless files
+Remove uncompiled python scripts
+Strip shared libraries
+Create archives
+cogeo
+cogeo
+Unzip Layer and move all items up one directory
+Copy in Lambda code and zip up new 'uber' Lambda
+========= test session starts =========
+platform darwin -- Python 3.7.6, pytest-5.3.5, py-1.8.1, pluggy-0.13.1
+rootdir: /Users/ciaran/dev/localstack_and_lambda_layers/lambda
+collected 1 item                                                                                                                                                                                       
+
+test_lambda.py .
+
+========= 1 passed in 28.79s =========
+```