diff --git a/README.md b/README.md
new file mode 100644
index 0000000..443f049
--- /dev/null
+++ b/README.md
@@ -0,0 +1,24 @@
+# Ledger
+
+## Development
+
+### Building locally
+
+```shell
+nix build
+```
+
+### Building dev environment
+
+#### For ide
+
+```shell
+nix build .#development-environment
+```
+
+#### For shell
+
+```shell
+nix develop
+```
+
diff --git a/flake.nix b/flake.nix
index 31d7637..b02dd6b 100644
--- a/flake.nix
+++ b/flake.nix
@@ -25,13 +25,21 @@
               # something that work.. ish
               rustc
               cargo
-              rustPlatform.rustcSrc gcc
+              rustfmt
+              rustPlatform.rustcSrc
+              gcc
+              cargo-tarpaulin
               ];
           };
 
 
         devShell = with pkgs; mkShell {
-          buildInputs = [ cargo rustc rustfmt pre-commit rustPackages.clippy ];
+          buildInputs = [cargo
+                         rustc
+                         rustfmt
+                         pre-commit
+                         rustPackages.clippy
+                         cargo-tarpaulin];
           RUST_SRC_PATH = rustPlatform.rustLibSrc;
         };
       });