add ddl

alice/backends/mysql/__init__.py

@@ -5,24 +5,4 @@ from alice.backends import DDL
 
 class MysqlDDL(DDL):
     schema_generator_cls = MySQLSchemaGenerator
-
-    def drop_table(self):
-        pass
-
-    def add_column(self):
-        pass
-
-    def drop_column(self):
-        pass
-
-    def add_index(self):
-        pass
-
-    def drop_index(self):
-        pass
-
-    def add_fk(self):
-        pass
-
-    def drop_fk(self):
-        pass
+    DIALECT = "mysql"