added flake and isntructions

Signed-off-by: Brendan Golden <git@brendan.ie>

flake.nix

@@ -0,0 +1,31 @@
+{
+  description = "UL Computer Society Open Governance";
+
+  inputs = {
+    nixpkgs.url = "nixpkgs/nixos-unstable";
+    utils.url   = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, utils }: utils.lib.eachDefaultSystem (system: 
+  let
+    pkgs = import nixpkgs { 
+      system = "${system}"; 
+      config = {
+        allowUnfree = true; 
+        permittedInsecurePackages = [
+          "electron-25.9.0"
+        ];
+      };
+    };
+  in rec {
+    # `nix develop`
+    devShell = pkgs.mkShell {
+      nativeBuildInputs = with pkgs; [ obsidian ];
+      shellHook = ''
+        ${pkgs.obsidian}/bin/obsidian &
+        BG_PID=$!
+        trap "kill -9 $BG_PID" EXIT
+      '';
+    };
+  });
+}