docs: add debuggability section

README.md

@@ -129,6 +129,59 @@ const cell = new BemCell({
 cell.id; // ➜ "button__text@desktop.css"
 ```
 
+Debuggability
+-------------
+
+In Node.js, `console.log()` calls `util.inspect()` on each argument without a formatting placeholder.
+
+`BemCell` has `inspect()` method to get custom string representation of the object.
+
+```js
+const BemCell = require('@bem/cell');
+const BemEntityName = require('@bem/entity-name');
+
+const cell = new BemCell({
+    entity: new BemEntityName({ block: 'input', mod: 'available' }),
+    tech: 'css'
+});
+
+console.log(cell);
+
+// ➜ BemCell { entity: { block: 'input', mod: { name: 'available' } }, tech: 'css' }
+```
+
+You can also convert `BemCell` object to `string`.
+
+```js
+const BemCell = require('@bem/cell');
+const BemEntityName = require('@bem/entity-name');
+
+const cell = new BemCell({
+    entity: new BemEntityName({ block: 'input', mod: 'available' }),
+    tech: 'css'
+});
+
+console.log(`cell: ${cell}`);
+
+// ➜ cell: input_available.css
+```
+
+Also `BemCell` has `toJson` method to support `JSON.stringify()` behaviour.
+
+```js
+const BemCell = require('@bem/cell');
+const BemEntityName = require('@bem/entity-name');
+
+const cell = new BemCell({
+    entity: new BemEntityName({ block: 'input', mod: 'available' }),
+    tech: 'css'
+});
+
+console.log(JSON.stringify(cell));
+
+// ➜ {"entity":{"block":"input","mod":{"name":"available","val":true}},"tech":"css"}
+```
+
 License
 -------