Updated Developers Guide (markdown)

Developers-Guide.md

@@ -1,3 +1,14 @@
+### Setting up your development environment (Linux)
+
+#### Requirements
+
+- [NodeJS](https://nodejs.org/en/download/package-manager/) & [Yarn](https://classic.yarnpkg.com/en/docs/install/#debian-stable)
+- [Golang 1.15+](https://golang.org/dl/)
+- [Python 3+](https://www.python.org/downloads/) & [Pipenv](https://pypi.org/project/pipenv/) (for `pre-commit` hooks) 
+- [gqlgen](https://gqlgen.com/)
+- [mage](https://magefile.org/) (can use the `cmd/mage/main.go` as an alternative to installing mage globally)
+
+
 ### Frontend
 
 #### Tools used