Add configurable limits for number of builds allowed under a namespace

We also support that limit being increased automatically once a successful billing charge has gone through

data/migrations/versions/152bb29a1bb3_add_maximum_build_queue_count_setting_.py

@@ -0,0 +1,26 @@
+"""Add maximum build queue count setting to user table
+
+Revision ID: 152bb29a1bb3
+Revises: 7367229b38d9
+Create Date: 2018-02-20 13:34:34.902415
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '152bb29a1bb3'
+down_revision = 'cbc8177760d9'
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import mysql
+
+def upgrade(tables):
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column('user', sa.Column('maximum_queued_builds_count', sa.Integer(), nullable=True))
+    # ### end Alembic commands ###
+
+
+def downgrade(tables):
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column('user', 'maximum_queued_builds_count')
+    # ### end Alembic commands ###