Replicate Solr Index

1. GET https://opensolr.com/solr_manager/api/replicate_index
2. Parameters:
   1. ​email - your opensolr registration email address
   2. api_key - your opensolr api_key
   3. ​index_name - the name of the master index. this index has to be created first.
   4. target_index - the name of the target replica indes. this index has to be created first.

3. Example: https://opensolr.com/solr_manager/api/replicate_index?email=PLEASE_LOG_IN&
   api_key=PLEASE_LOG_IN&index_name=master_index&target_index=replica_index