chore: flake.nix creating a devshell with all fullnode dependencies needed to run the fullnode

.envrc

@@ -0,0 +1,7 @@
+if [[ $(type -t use_flake) != function ]]; then
+  echo "ERROR: use_flake function missing."
+  echo "Please update direnv to v2.30.0 or later."
+  exit 1
+fi
+
+use flake

.gitignore

@@ -22,3 +22,6 @@ extras/docker/envvars
 /dist/
 /requirements.txt
 *.egg-info
+
+# Nix
+.direnv/

flake.nix

@@ -0,0 +1,40 @@
+{
+  description = "virtual environments";
+
+  inputs.devshell.url = "github:numtide/devshell";
+  inputs.flake-utils.url = "github:numtide/flake-utils";
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/master";
+
+  outputs = { self, flake-utils, devshell, nixpkgs }:
+
+    flake-utils.lib.eachDefaultSystem (system: {
+      devShells.default =
+        let
+          pkgs = import nixpkgs {
+            inherit system;
+            overlays = [ devshell.overlays.default ];
+          };
+        in
+          pkgs.mkShell {
+            buildInputs = [
+              pkgs.python310
+              pkgs.poetry
+              pkgs.rocksdb
+              pkgs.snappy
+              pkgs.openssl
+              pkgs.readline
+              pkgs.zlib
+              pkgs.xz
+              pkgs.bzip2
+              pkgs.lz4
+              pkgs.cmake
+            ];
+
+            shellHook = ''
+              export CFLAGS="-I${pkgs.rocksdb}/include"
+              export LDFLAGS="-L${pkgs.rocksdb}/lib"
+              poetry env use python3.10
+            '';
+          };
+    });
+}