Adding serial numbers when certificates with the same name are encoun… (#970)

* Adding serial numbers when certificates with the same name are encountered.

lemur/migrations/versions/ac483cfeb230_.py

@@ -0,0 +1,27 @@
+"""empty message
+
+Revision ID: ac483cfeb230
+Revises: b29e2c4bf8c9
+Create Date: 2017-10-11 10:16:39.682591
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = 'ac483cfeb230'
+down_revision = 'b29e2c4bf8c9'
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+
+def upgrade():
+    op.alter_column('certificates', 'name',
+                    existing_type=sa.VARCHAR(length=128),
+                    type_=sa.String(length=256))
+
+
+def downgrade():
+    op.alter_column('certificates', 'name',
+                    existing_type=sa.VARCHAR(length=256),
+                    type_=sa.String(length=128))