Remove ID column enforcement

Fixes first part of #5. When using the model generator in pop this enforcement
is already done:
https://github.com/gobuffalo/pop/blob/v4.6.3/soda/cmd/generate/model.go#L121

tables.go

@@ -108,18 +108,6 @@ func (f fizzer) CreateTable(name string, opts map[string]interface{}, help plush
 		}
 	}
 
-	var foundPrimary bool
-	for _, c := range t.Columns {
-		if c.Primary {
-			foundPrimary = true
-			break
-		}
-	}
-
-	if !foundPrimary {
-		t.Columns = append([]Column{INT_ID_COL}, t.Columns...)
-	}
-
 	if enabled, exists := t.Options["timestamps"]; !exists || enabled == true {
 		t.Timestamps()
 	}