added wrapper for hasOne + belongsTo and hasMany + belongsTo

examples/Associations/app.js

@@ -11,14 +11,9 @@ var Pet = sequelize.define('pet', {
 
 Person.hasMany('brothers')
 Person.hasMany('sisters')
-
-var fatherAssoc = Person.hasOne('father', Person)
-var motherAssoc = Person.hasOne('mother', Person)
-Person.belongsTo('father', Person, fatherAssoc)
-Person.belongsTo('mother', Person, motherAssoc)
-
-var petAssoc = Person.hasMany('pets', Pet)
-Pet.belongsTo('owner', Person, petAssoc)
+Person.hasOneAndBelongsTo('father', Person)
+Person.hasOneAndBelongsTo('mother', Person)
+Person.hasManyAndBelongsTo('pets', Pet, 'owner')
 
 Sequelize.chainQueries([{drop: sequelize}, {sync: sequelize}], function() {
   var person  = new Person({ name: 'Luke' }),

lib/sequelize/SequelizeTable.js

@@ -178,6 +178,11 @@ exports.SequelizeTable = function(Sequelize, sequelize, tableName, attributes, o
       }
     },
     
+    hasManyAndBelongsTo: function(assocName, _table, backAssocName) {
+      var assoc = table.hasMany(assocName, _table)
+      _table.belongsTo(backAssocName || assocName, table, assoc)
+    },
+    
     hasOne: function(assocName, _table) {
       var Factory     = new require("./Factory").Factory(Sequelize, sequelize),
           association = { name: assocName, table: _table, type: 'hasOne' }
@@ -188,6 +193,11 @@ exports.SequelizeTable = function(Sequelize, sequelize, tableName, attributes, o
       return association
     },
     
+    hasOneAndBelongsTo: function(assocName, _table, backAssocName) {
+      var assoc = table.hasOne(assocName, _table)
+      _table.belongsTo(backAssocName || assocName, table, assoc)
+    },
+    
     belongsTo: function(assocName, _table, backAssociation) {
       if(typeof backAssociation == 'undefined')
         throw new Error("Calling belongsTo with only two parameters is deprecated! Please take a look at the example in the repository!")