revert data-models/vote-model documentation

docs/server/source/data-models/index.rst

@@ -16,4 +16,4 @@ This section unpacks each one in turn.
    asset-model
    crypto-conditions
    block-model
-   ../schema/vote
+   vote-model

docs/server/source/data-models/vote-model.md

@@ -0,0 +1,20 @@
+# The Vote Model
+
+A vote has the following structure:
+
+```json
+{
+    "id": "<RethinkDB-generated ID for the vote>",
+    "node_pubkey": "<the public key of the voting node>",
+    "vote": {
+        "voting_for_block": "<id of the block the node is voting for>",
+        "previous_block": "<id of the block previous to this one>",
+        "is_block_valid": "<true|false>",
+        "invalid_reason": "<None|DOUBLE_SPEND|TRANSACTIONS_HASH_MISMATCH|NODES_PUBKEYS_MISMATCH",
+        "timestamp": "<Unix time when the vote was generated, provided by the voting node>"
+    },
+    "signature": "<signature of vote>"
+}
+```
+
+Note: The `invalid_reason` was not being used and may be dropped in a future version of BigchainDB. See [Issue #217](https://github.com/bigchaindb/bigchaindb/issues/217) on GitHub.