feat: Implement draft version of Step model

packages/backend/src/db/migrations/20211106214730_create_steps.ts

@@ -0,0 +1,18 @@
+import { Knex } from "knex";
+
+export async function up(knex: Knex): Promise<void> {
+  return knex.schema.createTable('steps', (table) => {
+    table.increments('id');
+    table.string('key').notNullable();
+    table.string('app_key').notNullable();
+    table.string('type').notNullable();
+    table.integer('connection_id').references('id').inTable('connections');
+    table.text('parameters')
+
+    table.timestamps(true, true);
+  });
+};
+
+export async function down(knex: Knex): Promise<void> {
+  return knex.schema.dropTable('steps');
+}