Added code syntax highlighting for tutorials

tutorials/many-to-many.md

@@ -1,5 +1,6 @@
 Many-to-many associations can be created with {@link Model#belongsToMany belongsToMany}, and {@link Model#through through} relation types.
 
+```js
     var Book = bookshelf.Model.extend({
       tableName: 'books',
       authors: function() {
@@ -13,9 +14,10 @@ Many-to-many associations can be created with {@link Model#belongsToMany belongs
         return this.belongsToMany(Book);
       }
     });
-
+```
 A Knex migration for the above relationship could be created with:
 
+```js
     exports.up = function(knex, Promise) {
       return knex.schema.createTable('books', function(table) {
         table.increments('id').primary();
@@ -34,3 +36,4 @@ A Knex migration for the above relationship could be created with:
         .dropTable('authors')
         .dropTable('authors_books');
     };
+```

tutorials/one-to-many.md

@@ -1,5 +1,6 @@
 One-to-many associations can be created with {@link Model#belongsTo belongsTo}, {@link Model#hasMany hasMany}, {@link Model#morphMany morphMany} / {@link Model#morphTo morphTo}, and some of the {@link Model#through through} relation types.
 
+```js
     var Book = bookshelf.Model.extend({
       tableName: 'books',
       pages: function() {
@@ -13,9 +14,10 @@ One-to-many associations can be created with {@link Model#belongsTo belongsTo},
         return this.belongsTo(Book);
       }
     });
-
+```
 A Knex migration for the above relationship could be created with:
 
+```js
     exports.up = function(knex, Promise) {
       return knex.schema.createTable('books', function(table) {
         table.increments('id').primary();
@@ -31,3 +33,4 @@ A Knex migration for the above relationship could be created with:
       return knex.schema.dropTable('books')
         .dropTable('pages');
     };
+```

tutorials/one-to-one.md

@@ -1,5 +1,6 @@
 One-to-one associations can be created with {@link Model#belongsTo belongsTo}, {@link Model#hasOne hasOne}, and {@link Model#morphOne morphOne} relation types.
 
+```js
     var Book = bookshelf.Model.extend({
       tableName: 'books',
       summary: function() {
@@ -13,9 +14,10 @@ One-to-one associations can be created with {@link Model#belongsTo belongsTo}, {
         return this.belongsTo(Book);
       }
     });
-
+```
 A Knex migration for the above relationship could be created with:
 
+```js
     exports.up = function(knex, Promise) {
       return knex.schema.createTable('books', function(table) {
         table.increments('id').primary();
@@ -31,3 +33,4 @@ A Knex migration for the above relationship could be created with:
       return knex.schema.dropTable('books')
         .dropTable('summaries');
     };
+```

tutorials/parse-and-format.md

@@ -5,6 +5,7 @@ parse.
 This can be done with the model's {@link Model#parse parse} and {@link Model#format format}
 methods:
 
+```js
     Book = bookshelf.Model.extend({
       tableName: 'books',
       parse: function(response) {
@@ -16,9 +17,11 @@ methods:
         return attributes;
       }
     });
+```
 
 A very common use case for this is converting camelCase attributes to snake_case column names and vice-versa:
 
+```js
     Book = bookshelf.Model.extend({
       tableName: 'books',
       parse: function(response) {
@@ -32,3 +35,4 @@ A very common use case for this is converting camelCase attributes to snake_case
         });
       }
     });
+```

tutorials/polymorphic.md

@@ -1,5 +1,6 @@
 With polymorphic associations, a model can belong to more than one other model, on a single association. For example, you might have a photo model that belongs to either a `Site` model or a `Post` model. Here’s how this could be declared:
 
+```js
     var Site = bookshelf.Model.extend({
       tableName: 'sites',
       photo: function() {
@@ -20,6 +21,7 @@ With polymorphic associations, a model can belong to more than one other model,
         return this.morphTo('imageable', Site, Post);
       }
     });
+```
 
 Optionally, if you wish to use column names other than the `name` suffixed with `_type` and `_id` (for example, if you use a different naming convention in your database), you may specify custom `columnNames`. This argument, when specified, expects an array containing the substitute `_type` and `_id` columns, respectively.