feat: update readme file with basic description and usage

README.md

@@ -1 +1,64 @@
 # mathml-to-latex
+
+It converts [MathML](https://en.wikipedia.org/wiki/MathML) to [LaTeX](https://pt.wikipedia.org/wiki/LaTeX).
+
+## Instalation
+
+If you use NPM
+
+```
+npm install mathml-to-latex --save
+```
+
+If you use Yarn
+
+```
+yarn add mathml-to-latex
+```
+
+## Usage
+
+```javascript
+const Mathml2latex = require('mathml-to-latex');
+
+const mathml = `
+      <math>
+        <mrow>
+          <mn>a</mn>
+          <mo>+</mo>
+          <mn>b</mn>
+        </mrow>
+      </math>
+      `;
+
+Mathml2latex.convert(mathml);
+// => a + b
+```
+
+```javascript
+const Mathml2latex = require('mathml-to-latex');
+
+const mathml = `
+    <math>
+        <mrow>
+            <mi>A</mi>
+            <mo>=</mo>
+            <mfenced open = "[" close="]">
+            <mtable>
+                <mtr>
+                <mtd><mi>x</mi></mtd>
+                <mtd><mi>y</mi></mtd>
+                </mtr>
+                <mtr>
+                <mtd><mi>z</mi></mtd>
+                <mtd><mi>w</mi></mtd>
+                </mtr>
+            </mtable>
+            </mfenced>
+        </mrow>
+    </math>
+    `;
+
+Mathml2latex.convert(mathml);
+// => A = \begin{bmatrix} x & y \\ z & w \end{bmatrix}
+```