Added README.md (#10)

* Added README.md

* Fixed typo's

README.md

@@ -0,0 +1,280 @@
+## Introduction ##
+
+The Predis Vector Library (PredisVL) is a PHP client for AI applications leveraging Redis.
+
+Designed for:
+- Vector similarity search
+- Recommendation engine
+
+A perfect tool for Redis-based applications, incorporating capabilities like vector-based semantic search,
+full-text search, and geo-spatial search.
+
+## Getting started ##
+
+### Installation ###
+
+For now PredisVL isn't available at packagist.org, but you can still install it via Composer by specifying [GitHub 
+repository](https://github.com/vladvildanov/predis-vl) in your composer.json file.
+
+```shell
+{
+    "repositories": [
+        {
+            "type": "github",
+            "url": "https://github.com/vladvildanov/predis-vl.git"
+        }
+    ]
+}
+```
+```shell
+composer install vladvildanov/predis-vl
+```
+
+### Setting up Redis ####
+
+Choose from multiple Redis deployment options:
+1. [Redis Cloud](https://redis.com/try-free/): Managed cloud database (free tier available)
+2. [Redis Stack](https://redis.io/docs/install/install-stack/docker/): Docker image for development
+```shell
+docker run -d --name redis-stack -p 6379:6379 -p 8001:8001 redis/redis-stack:latest
+```
+3. [Redis Enterprise](https://redis.com/redis-enterprise/advantages/): Commercial, self-hosted database
+
+## What's included? ##
+
+### Redis index management ###
+
+1. Design your schema that models your dataset with one of the available Redis data structures (HASH, JSON)
+and indexable fields (e.g. text, tags, numerics, geo, and vectors).
+
+Load schema as a dictionary:
+```php
+$schema = [
+    'index' => [
+        'name' => 'products',
+        'prefix' => 'product:',
+        'storage_type' => 'hash',
+    ],
+    'fields' => [
+        'id' => [
+            'type' => 'numeric',
+        ],
+        'categories' => [
+            'type' => 'tag',
+        ],
+        'description' => [
+            'type' => 'text',
+        ],
+        'description_embedding' => [
+             'type' => 'vector',
+             'dims' => 3,
+             'datatype' => 'float32',
+             'algorithm' => 'flat',
+             'distance_metric' => 'cosine'
+        ],
+    ],
+];
+```
+2. Create a SearchIndex object with an input schema and client connection to be able to interact with your Redis index
+```php
+use Predis\Client;
+use Vladvildanov\PredisVl\Index\SearchIndex;
+
+$client = new Client();
+$index = new SearchIndex($client, $schema);
+
+// Creates index in the Redis
+$index->create();
+```
+3. Load/fetch your data from index. If you have a hash index data should be loaded as key-value pairs
+, for json type data loads as json string.
+```php
+$data = ['id' => '1', 'count' => 10, 'id_embeddings' => VectorHelper::toBytes([0.000001, 0.000002, 0.000003])];
+
+// Loads given dataset associated with given key.
+$index->load('key', $data);
+
+// Fetch dataset corresponding to given key
+$index->fetch('key');
+```
+
+### Realtime search ###
+
+Define queries and perform advanced search over your indices, including combination of vectors and variety of filters.
+
+**VectorQuery** - flexible vector-similarity semantic search with customizable filters
+```php
+use Vladvildanov\PredisVl\Query\VectorQuery;
+
+$query = new VectorQuery(
+    [0.001, 0.002, 0.03],
+    'description_embedding',
+    null,
+    3
+);
+
+// Run vector search against vector field specified in schema.
+$results = $index->query($query);
+```
+
+Incorporate complex metadata filters on your queries:
+```php
+use Vladvildanov\PredisVl\Query\Filter\TagFilter;
+use Vladvildanov\PredisVl\Enum\Condition;
+
+$filter = new TagFilter(
+    'categories',
+    Condition::equal,
+    'foo'
+);
+
+$query = new VectorQuery(
+    [0.001, 0.002, 0.03],
+    'description_embedding',
+    null,
+    10,
+    true,
+    2,
+    $filter
+);
+
+// Results will be filtered by tag field values.
+$results = $index->query($query);
+```
+
+### Filter types ###
+
+#### Numeric ####
+
+Numeric filters could be applied to numeric fields. 
+Supports variety of conditions applicable for scalar types (==, !=, <, >, <=, >=).
+More information [here](https://redis.io/docs/interact/search-and-query/query/range/).
+```php
+use Vladvildanov\PredisVl\Query\Filter\NumericFilter;
+use Vladvildanov\PredisVl\Enum\Condition;
+
+$equal = new NumericFilter('numeric', Condition::equal, 10);
+$notEqual = new NumericFilter('numeric', Condition::notEqual, 10);
+$greaterThan = new NumericFilter('numeric', Condition::greaterThan, 10);
+$greaterThanOrEqual = new NumericFilter('numeric', Condition::greaterThanOrEqual, 10);
+$lowerThan = new NumericFilter('numeric', Condition::lowerThan, 10);
+$lowerThanOrEqual = new NumericFilter('numeric', Condition::lowerThanOrEqual, 10);
+```
+
+#### Tag ####
+
+Tag filters could be applied to tag fields. Single or multiple values can be provided, single values supports only 
+equality conditions (==, !==), for multiple tags additional conjunction (AND, OR) could be specified.
+More information [here](https://redis.io/docs/interact/search-and-query/advanced-concepts/tags/)
+```php
+use Vladvildanov\PredisVl\Query\Filter\TagFilter;
+use Vladvildanov\PredisVl\Enum\Condition;
+use Vladvildanov\PredisVl\Enum\Logical;
+
+$singleTag = new TagFilter('tag', Condition::equal, 'value')
+$multipleTags = new TagFilter('tag', Condition::notEqual, [
+    'conjunction' => Logical::or,
+    'tags' => ['value1', 'value2']
+])
+```
+
+#### Text ####
+
+Text filters could be applied to text fields. Values can be provided as a single word or multiple words with
+specified condition. Empty value corresponds to all values (*). 
+More information [here](https://redis.io/docs/interact/search-and-query/query/full-text/)
+```php
+use Vladvildanov\PredisVl\Query\Filter\TextFilter;
+use Vladvildanov\PredisVl\Enum\Condition;
+
+$single = new TextFilter('text', Condition::equal, 'foo');
+
+// Matching foo AND bar
+$multipleAnd = new TextFilter('text', Condition::equal, 'foo bar');
+
+// Matching foo OR bar
+$multipleOr = new TextFilter('text', Condition::equal, 'foo|bar');
+
+// Perform fuzzy search
+$fuzzy = new TextFilter('text', Condition::equal, '%foobaz%');
+```
+
+#### Geo ####
+
+Geo filters could be applied to geo fields. Supports only equality conditions, 
+value should be specified as specific-shape array. 
+More information [here](https://redis.io/docs/interact/search-and-query/query/geo-spatial/)
+```php
+use Vladvildanov\PredisVl\Query\Filter\GeoFilter;
+use Vladvildanov\PredisVl\Enum\Condition;
+use Vladvildanov\PredisVl\Enum\Unit;
+
+$geo = new GeoFilter('geo', Condition::equal, [
+    'lon' => 10.111,
+    'lat' => 11.111,
+    'radius' => 100,
+    'unit' => Unit::kilometers
+]);
+```
+
+#### Aggregate ####
+
+To apply multiple filters to a single query use AggregateFilter. 
+If there's the same logical operator that should be applied for each filter you can pass values in constructor,  
+if you need a specific combination use `and()` and `or()` methods to create combined filter.
+```php
+use Vladvildanov\PredisVl\Query\Filter\AggregateFilter;
+use Vladvildanov\PredisVl\Query\Filter\TextFilter;
+use Vladvildanov\PredisVl\Query\Filter\NumericFilter;
+use Vladvildanov\PredisVl\Enum\Condition;
+use Vladvildanov\PredisVl\Enum\Logical;
+
+$aggregate = new AggregateFilter([
+    new TextFilter('text', Condition::equal, 'value'),
+    new NumericFilter('numeric', Condition::greaterThan, 10)
+], Logical::or);
+
+$combinedAggregate = new AggregateFilter();
+$combinedAggregate
+    ->and(
+        new TextFilter('text', Condition::equal, 'value'),
+        new NumericFilter('numeric', Condition::greaterThan, 10)
+    )->or(
+        new NumericFilter('numeric', Condition::lowerThan, 100)
+    );
+```
+
+## Vectorizers ##
+
+To be able to effectively create vector representations for your indexed data or queries, you have to use 
+[LLM's](https://en.wikipedia.org/wiki/Large_language_model). There's a variety of vectorizers that provide integration
+with popular embedding models.
+
+The only required option is your API key specified as environment variable or configuration option.
+
+### OpenAI ###
+```php
+use Vladvildanov\PredisVl\Vectorizer\Factory;
+
+putenv('OPENAI_API_TOKEN=your_token');
+
+$factory = new Factory();
+$vectorizer = $factory->createVectorizer('openai');
+
+// Creates vector representation of given text.
+$embedding = $vectorizer->embed('your_text')
+
+// Creates a single vector representation from multiple chunks.
+$mergedEmbedding = $vectorizer->batchEmbed(['first_chunk', 'second_chunk']);
+```
+
+### VectorHelper ###
+
+When you perform vector queries against Redis or load hash data into index that contains vector field data, 
+your vector should be represented as a blob string. VectorHelper allows you to create
+blob representation from your vector represented as array of floats.
+```php
+use Vladvildanov\PredisVl\VectorHelper;
+
+$blobVector = VectorHelper::toBytes([0.001, 0.002, 0.003]);
+```