Finish implementation of delete field from schema

spec/Schema.spec.js

@@ -520,4 +520,50 @@ describe('Schema', () => {
       });
     })
   });
+
+  it('can delete string fields and resave as number field', done => {
+    var obj1 = hasAllPODobject();
+    var obj2 = hasAllPODobject();
+    var p = Parse.Object.saveAll([obj1, obj2])
+    .then(() => config.database.loadSchema())
+    .then(schema => schema.deleteField('aString', 'HasAllPOD', config.database.db, 'test_'))
+    .then(() => new Parse.Query('HasAllPOD').get(obj1.id))
+    .then(obj1 => {
+      expect(obj1.get('aString')).toEqual(undefined);
+      obj1.set('aString', ['not a string', 'this time']);
+      obj1.save()
+      .then(obj1 => {
+        expect(obj1.get('aString')).toEqual(['not a string', 'this time']);
+        return new Parse.Query('HasAllPOD').get(obj2.id);
+      })
+      .then(obj2 => {
+        expect(obj2.get('aString')).toEqual(undefined);
+        done();
+      });
+    })
+  });
+
+  it('can delete pointer fields and resave as string', done => {
+    var obj1 = new Parse.Object('NewClass');
+    obj1.save()
+    .then(() => {
+      obj1.set('aPointer', obj1);
+      return obj1.save();
+    })
+    .then(obj1 => {
+      expect(obj1.get('aPointer').id).toEqual(obj1.id);
+    })
+    .then(() => config.database.loadSchema())
+    .then(schema => schema.deleteField('aPointer', 'NewClass', config.database.db, 'test_'))
+    .then(() => new Parse.Query('NewClass').get(obj1.id))
+    .then(obj1 => {
+      expect(obj1.get('aPointer')).toEqual(undefined);
+      obj1.set('aPointer', 'Now a string');
+      return obj1.save();
+    })
+    .then(obj1 => {
+      expect(obj1.get('aPointer')).toEqual('Now a string');
+      done();
+    });
+  });
 });