docs: enhanced cli usage and overral readme documentation

Author: luistak

README.md

@@ -23,35 +23,62 @@ Given a few options you can gets details about how your library is being importe
 ```js
 import { getPackagesUsages } from 'pkg-usage';
 
-const usages = getPackagesUsages({
+const usages: PackageUsage[] = getPackagesUsages({
   packages: ['react'],
   fileGlobs: `**/**.ts`,
 });
 
 console.log(usages);
 ```
 
-Output
-
-```json
-[
-  {
-    count: 1,
-    files: [
-      {
-        defaultImport: undefined,
-        name: `${fileName}.ts`,
-        namedImports: imports,
-      },
-    ],
-    name: pkg,
-    version,
-  }
-]
+Package Usage types
+
+```ts
+export type FileUsage = {
+  name: string;
+  filePath: string;
+  defaultImport: string | undefined;
+  namedImports: string[];
+};
+
+export type PackageUsage = {
+  name: string;
+  count: number;
+  files?: FileUsage[];
+  version?: string;
+};
 ```
 
-## Current features:
+## CLI usage
 
-- The package version
-- How many files are importing your `package`
-- What are the default and named imports by file
+| Options                  | Description                          | Example                                        |
+| ------------------------ | ------------------------------------ | ---------------------------------------------- |
+| -p, --packages           | Packages to analyze                  | -p vue,vuex or --packages="react,redux"        |
+| -f, --file-globs         | Files to analyze based on file globs | -f "_.(ts\|tsx)" or --file-globs="_.(js\|jsx)" |
+| -cwd, --package-json-CWD | Directory to start from              | -cwd "/path/to/start/from"                     |
+
+### npx
+
+[`npx`](https://medium.com/@maybekatz/introducing-npx-an-npm-package-runner-55f7d4bd282b) is a package runner tool
+
+```bash
+npx pkg-usage -p "react,redux" --f "**/*.(ts|tsx)"
+```
+
+Or
+
+```bash
+npx pkg-usage --packages="vue,vuex" --file-globs="**/*.(js|jsx)"
+```
+
+If you use npm 5.1 or earlier, you can't use npx. Instead, install it globally:
+
+```bash
+npm install -g pkg-usage
+```
+
+Now you can run:
+
+```bash
+pkg-usage -p "react,redux" --f "**/*.(ts|tsx)"
+```

package.json

@@ -1,6 +1,6 @@
 {
   "name": "pkg-usage",
-  "version": "0.2.1-pre",
+  "version": "0.2.1",
   "description": "Npm package usage metrics",
   "main": "dist/src/index.js",
   "files": [
@@ -9,6 +9,13 @@
     "example",
     "scripts"
   ],
+  "keywords": [
+    "node",
+    "npm",
+    "package",
+    "usage",
+    "resources"
+  ],
   "bin": {
     "pkg-usage": "./scripts/pkg-usage.js"
   },