Increase size of column name in table ab_view_meu (apache#6532)

* Create migration script

* Use batch operation for ALTER COLUMN

superset/migrations/versions/cefabc8f7d38_increase_size_of_name_column_in_ab_view_.py

@@ -0,0 +1,34 @@
+"""Increase size of name column in ab_view_menu
+
+Revision ID: cefabc8f7d38
+Revises: 6c7537a6004a
+Create Date: 2018-12-13 15:38:36.772750
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = 'cefabc8f7d38'
+down_revision = '6c7537a6004a'
+
+from alembic import op
+import sqlalchemy as sa
+
+
+def upgrade():
+    with op.batch_alter_table('ab_view_menu') as batch_op:
+        batch_op.alter_column(
+            'name',
+            existing_type=sa.String(length=100),
+            existing_nullable=False,
+            type_=sa.String(length=255),
+            nullable=False)
+
+
+def downgrade():
+    with op.batch_alter_table('ab_view_menu') as batch_op:
+        batch_op.alter_column(
+            'name',
+            existing_type=sa.String(length=255),
+            existing_nullable=False,
+            type_=sa.String(length=100),
+            nullable=False)