add installation and usage

Author: quantonganh

README.md

@@ -2,3 +2,37 @@
 A simple language server to just insert snippets into Helix (and other text editor, IDE)
 
 https://quantonganh.com/2023/07/31/create-snippets-in-helix
+
+## Installation
+
+### Install via go
+
+Due to the presence of a `replace` directive in the [go.mod](https://github.com/quantonganh/snippets-ls/blob/main/go.mod#L13) file, [`go install` cannot be used](https://github.com/golang/go/issues/44840). You have to clone and build the package manually:
+
+```sh
+$ git clone git@github.com:quantonganh/snippets-ls.git
+$ cd snippets-ls
+$ go build -o ~/go/bin/snippets-ls main.go
+```
+
+Don't forget to append `~/go/bin` to your `$PATH`.
+
+## Usage
+
+Create your own snippets follow [VSCode syntax](https://code.visualstudio.com/docs/editor/userdefinedsnippets#_create-your-own-snippets). Alternatively, you can make use of [pre-existing](https://github.com/microsoft/vscode-go/blob/master/snippets/go.json) [sample](https://github.com/rust-lang/vscode-rust/blob/master/snippets/rust.json) for various programming languages.
+
+Update your configuration file located at `~/.config/helix/languages.toml`:
+
+```toml
+[[language]]
+name = "go"
+formatter = { command = "goimports"}
+language-servers = ["gopls", "snippets-ls"]
+
+[language-server.snippets-ls]
+command = "snippets-ls"
+args = ["-config", "/Users/quantong/.config/helix/go-snippets.json"]
+```
+
+Subsequently, as you start working on your file, input a snippet prefix to observe the suggestion.
+If it does not work, take a look at `~/.cache/helix/helix.log` for additional insights.