describeTable + addColumn

lib/query-interface.js

-var Utils = require('./utils')
+var Utils     = require('./utils')
+  , DataTypes = require('./data-types')
 
 module.exports = (function() {
   var QueryInterface = function(sequelize) {
@@ -86,8 +87,39 @@ module.exports = (function() {
     }).run()
   }
 
-  QueryInterface.prototype.addColumn = function() {
+  QueryInterface.prototype.describeTable = function(tableName) {
+    var self = this
+
+    return new Utils.CustomEventEmitter(function(emitter) {
+      self.sequelize.query('DESCRIBE `' + tableName + '`;', null, { raw: true }).success(function(data) {
+        emitter.emit('success', data)
+      }).error(function(err) {
+        emitter.emit('failure', err)
+      })
+    }).run()
+  }
 
+  QueryInterface.prototype.addColumn = function(tableName, attributeName, dataTypeOrOptions) {
+    var attributes = {}
+
+    if(Utils._.values(DataTypes).indexOf(dataTypeOrOptions) > -1)
+      attributes[attributeName] = { type: dataTypeOrOptions, allowNull: false }
+    else
+      attributes[attributeName] = dataTypeOrOptions
+
+    var options = Utils.simplifyAttributes(attributes)
+      , query   = this.QueryGenerator.addColumnQuery(tableName, options)
+      , self    = this
+
+    return new Utils.CustomEventEmitter(function(emitter) {
+      self.sequelize.query(query).success(function() {
+        self.emit('addColumn', null)
+        emitter.emit('success', null)
+      }).error(function(err) {
+        self.emit('addColumn', err)
+        emitter.emit('failure', err)
+      })
+    }).run()
   }
 
   QueryInterface.prototype.removeColumn = function() {