chore: add gitignore and build configuration

foundry.toml

@@ -0,0 +1,10 @@
+[profile.default]
+src = "src"
+out = "out"
+libs = ["lib"]
+solc = "/home/foksiu/.local/bin/solc"
+optimizer = true
+optimizer_runs = 200
+evm_version = "cancun"
+
+# See more config options https://github.com/foundry-rs/foundry/blob/master/crates/config/README.md#all-options