add README.md

README.md

@@ -1,2 +1,66 @@
 # nosnakecase
 nosnakecase is a linter that detects snake case of variable naming and function name.
+
+## Instruction
+
+```sh
+go install github.com/sivchari/nosnakecase/cmd/nosnakecase@latest
+```
+
+## Usage
+
+```go
+package sandbox
+
+func a_() {
+}
+
+func b(a_a int) {
+}
+
+func c() (c_c int) {
+    c_c = 1
+	return c_c
+}
+
+func d() {
+	var d_d int
+	_ = d_d // It's never detected, because `_` is meaningful in Go and `d_d` is already detected.
+}
+```
+
+```console
+go vet -vettool=(which nosnakecase) ./...
+
+# command-line-arguments
+./main.go:3:6: a_ is used under score. You should use mixedCap or MixedCap.
+./main.go:6:8: a_a is used under score. You should use mixedCap or MixedCap.
+./main.go:10:2: c_c is used under score. You should use mixedCap or MixedCap.
+./main.go:11:9: c_c is used under score. You should use mixedCap or MixedCap.
+./main.go:9:11: c_c is used under score. You should use mixedCap or MixedCap.
+./main.go:15:6: d_d is used under score. You should use mixedCap or MixedCap.
+```
+
+## CI
+
+### CircleCI
+
+```yaml
+- run:
+    name: install nosnakecase
+    command: go install github.com/sivchari/nosnakecase/cmd/nosnakecase@latest
+
+- run:
+    name: run nosnakecase
+    command: go vet -vettool=`which nosnakecase` ./...
+```
+
+### GitHub Actions
+
+```yaml
+- name: install nosnakecase
+  run: go install github.com/sivchari/nosnakecase/cmd/nosnakecase@latest
+
+- name: run nosnakecase
+  run: go vet -vettool=`which nosnakecase` ./...
+```