Added short docs to the README (#13)

README.md

@@ -2,7 +2,7 @@
   Fast Node Manager (<code>fnm</code>) <a href="https://dev.azure.com/galstar0385/fnm/_build/latest?definitionId=1?branchName=master"><img alt="Build Status" src="https://dev.azure.com/galstar0385/fnm/_apis/build/status/Schniz.fnm?branchName=master" /></a>
 </h1>
 
-> :rocket: Fast and simple Node.js version manager, built in ReasonML 
+> :rocket: Fast and simple Node.js version manager, built in ReasonML
 
 <div align="center">
   <img src="./docs/fnm.svg" alt="Blazing fast!">
@@ -24,13 +24,37 @@
   ```bash
   eval `fnm env`
   ```
-  
+
   If you are using [fish shell](https://fishshell.com/), add this line to your `config.fish` file:
-  
+
   ```fish
   eval (fnm env --fish)
   ```
 
+## Usage
+
+You can always use `fnm --help` to read the docs:
+
+### `fnm install [VERSION]`
+
+Installs `[VERSION]`. If no version provided, it will install the version specified in the `.nvmrc` file located in the current working directory.
+
+### `fnm use [VERSION]`
+
+Activates `[VERSION]` as the current Node version. If no version provided, it will activate the version specified in the `.nvmrc` file located in the current working directory.
+
+### `fnm ls`
+
+Lists the installed Node versions.
+
+### `fnm ls-remote`
+
+Lists the Node versions available to download remotely.
+
+### `fnm env [--fish]`
+
+Prints the required shell commands in order to configure your shell, Bash compliant by default. Provide `--fish` to output the Fish-compliant version.
+
 ## Future Plans
 - [ ] Add a simpler way of installing it (`curl | bash`?)
 - [ ] Feature: make versions complete the latest: `10` would infer the latest minor and patch versions of node 10. `10.1` would infer the latest patch version of node 10.1