Fix m2m: only add fk when hasMany have no "through"

docs/model.md

@@ -181,7 +181,7 @@ TODO: document
 
 ### hasAndBelongsToMany
 
-TODO: implement and document
+TODO: document
 
 ## SEE ALSO
 

lib/relations.js

@@ -94,6 +94,7 @@ Model.hasMany = function hasMany(anotherClass, params) {
                 d.destroy(done);
             });
         };
+        delete scopeMethods.destroy;
     }
     defineScope(this.prototype, params.through || anotherClass, methodName, function () {
         var filter = {};
@@ -106,8 +107,10 @@ Model.hasMany = function hasMany(anotherClass, params) {
         return filter;
     }, scopeMethods);
 
+    if (!params.through) {
         // obviously, anotherClass should have attribute called `fk`
         anotherClass.schema.defineForeignKey(anotherClass.modelName, fk);
+    }
 
     function find(id, cb) {
         anotherClass.find(id, function (err, inst) {

test/relations.test.js

@@ -229,8 +229,6 @@ describe('relations', function() {
             });
         });
 
-        it('should allow to destroy instance and connection');
-
     });
 
 });