drop table pipet_usage (issue #137)

database/migrations/2021_07_22_141302_drop_pipet_usage_table.php

+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+class DropPipetUsageTable extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        Schema::dropIfExists('pipet_usage');
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    { 
+	Schema::create('pipet_usage', function (Blueprint $table) {
+        	$table->bigIncrements('id');
+		$table->string('name', 100)->nullable($value = false);
+
+		$table->timestamp('created_at')->useCurrent();
+		$table->timestamp('updated_at')->useCurrent();
+        });
+    }
+}