feat: Create execution model

packages/backend/src/db/migrations/20220219093113_create_executions.ts

@@ -0,0 +1,15 @@
+import { Knex } from 'knex';
+
+export async function up(knex: Knex): Promise<void> {
+  return knex.schema.createTable('executions', (table) => {
+    table.increments('id');
+    table.integer('flow_id').references('id').inTable('flows');
+    table.boolean('test_run').notNullable().defaultTo(false);
+
+    table.timestamps(true, true);
+  });
+}
+
+export async function down(knex: Knex): Promise<void> {
+  return knex.schema.dropTable('executions');
+}