[feat]: add models bind to eco database

app/eco/models/customer.py

@@ -0,0 +1,18 @@
+from sqlalchemy import Column, String, Date, Integer
+from sqlalchemy.orm import relationship
+from app.extensions import db
+
+
+class Customer(db.Model):
+    __tablename__ = 'customers'
+    __bind_key__ = 'eco'
+
+    id = Column(Integer, primary_key=True)
+    affiliate_code = Column(String(3), nullable=False)
+    customer_id = Column(String(9), unique=True, nullable=False)
+    msisdn = Column(String(15), nullable=True)
+    created_at = Column(Date, nullable=False)
+
+
+    def __repr__(self):
+        return f"<Customer(id={self.id}, customer_id={self.customer_id}, msisdn={self.msisdn})>"