Don't remove XML mappings

src/Resources/config/doctrine/ProductVariant.orm.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8"?>
+<doctrine-mapping xmlns="http://doctrine-project.org/schemas/orm/doctrine-mapping"
+                  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+                  xsi:schemaLocation="http://doctrine-project.org/schemas/orm/doctrine-mapping http://doctrine-project.org/schemas/orm/doctrine-mapping.xsd"
+>
+
+    <mapped-superclass name="Brille24\SyliusTierPricePlugin\Entity\ProductVariant" table="sylius_product_variant">
+        <one-to-many target-entity="Brille24\SyliusTierPricePlugin\Entity\TierPrice" mapped-by="productVariant" field="tierPrices" orphan-removal="true">
+            <cascade>
+                <cascade-all />
+            </cascade>
+            <order-by>
+                <order-by-field name="customerGroup" direction="ASC"/>
+                <order-by-field name="qty" direction="ASC"/>
+            </order-by>
+        </one-to-many>
+    </mapped-superclass>
+</doctrine-mapping>

src/Resources/config/doctrine/TierPrice.orm.xml

@@ -0,0 +1,35 @@
+<?xml version="1.0" encoding="utf-8"?>
+<doctrine-mapping xmlns="http://doctrine-project.org/schemas/orm/doctrine-mapping"
+                  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+                  xsi:schemaLocation="http://doctrine-project.org/schemas/orm/doctrine-mapping http://doctrine-project.org/schemas/orm/doctrine-mapping.xsd"
+>
+
+    <mapped-superclass
+            name="Brille24\SyliusTierPricePlugin\Entity\TierPrice"
+            repository-class="Brille24\SyliusTierPricePlugin\Repository\TierPriceRepository"
+            table="brille24_tierprice"
+    >
+        <id name="id" type="integer" column="id">
+            <generator strategy="AUTO"/>
+        </id>
+
+        <field name="price" type="integer" column="price" />
+        <field name="qty" type="integer" column="qty" />
+
+        <many-to-one target-entity="Sylius\Component\Channel\Model\ChannelInterface" field="channel">
+            <join-column name="channel_id" />
+        </many-to-one>
+
+        <many-to-one target-entity="Sylius\Component\Product\Model\ProductVariantInterface" field="productVariant" inversed-by="tierPrices">
+            <join-column name="product_variant_id" />
+        </many-to-one>
+
+	    <many-to-one target-entity="Sylius\Component\Customer\Model\CustomerGroupInterface" field="customerGroup">
+            <join-column name="customer_group_id" />
+        </many-to-one>
+
+        <unique-constraints>
+            <unique-constraint columns="qty,channel_id,product_variant_id,customer_group_id" name="no_duplicate_prices"/>
+        </unique-constraints>
+    </mapped-superclass>
+</doctrine-mapping>