Use a more reasonable index name for join table unique key

lib/associations/has-many.js

@@ -172,7 +172,8 @@ module.exports = (function() {
         combinedTableAttributes[this.identifier] = {type: sourceKeyType, primaryKey: true}
         combinedTableAttributes[this.foreignIdentifier] = {type: targetKeyType, primaryKey: true}
       } else { 
-        var uniqueKey = this.identifier + this.foreignIdentifier
+        var uniqueKey = [this.through.tableName, this.identifier, this.foreignIdentifier, 'unique'].join('_')
+        console.log(uniqueKey)
         combinedTableAttributes[this.identifier] = {type: sourceKeyType, unique: uniqueKey}
         combinedTableAttributes[this.foreignIdentifier] = {type: targetKeyType, unique: uniqueKey}
       }