Merge pull request ryanmcdermott#90 from vsemozhetbyt/single-quotes

use single quotes consistently

Author: ryanmcdermott

README.md

@@ -1411,7 +1411,7 @@ classes until you find yourself needing larger and more complex objects.
 ```javascript
 const Animal = function(age) {
   if (!(this instanceof Animal)) {
-    throw new Error("Instantiate Animal with `new`");
+    throw new Error('Instantiate Animal with `new`');
   }
 
   this.age = age;
@@ -1421,7 +1421,7 @@ Animal.prototype.move = function() {};
 
 const Mammal = function(age, furColor) {
   if (!(this instanceof Mammal)) {
-    throw new Error("Instantiate Mammal with `new`");
+    throw new Error('Instantiate Mammal with `new`');
   }
 
   Animal.call(this, age);
@@ -1434,7 +1434,7 @@ Mammal.prototype.liveBirth = function() {};
 
 const Human = function(age, furColor, languageSpoken) {
   if (!(this instanceof Human)) {
-    throw new Error("Instantiate Human with `new`");
+    throw new Error('Instantiate Human with `new`');
   }
 
   Mammal.call(this, age, furColor);