added new memory steps (#35)

Author: AlexGalichenko

docs/Steps/memory.md

@@ -83,6 +83,21 @@ example:
 ```gherkin
 When I save 'value' to memory as 'key'
 ```
+
+---
+### I set {string} = {string}
+
+Save value to memory
+
+| param |  type  | description | example |
+|:-----:|:------:|:-----------:|:-------:|
+|  key  | string |     key     |         |
+| value | string |    value    |         |
+
+example:
+```gherkin
+When I set 'key' = 'value'
+```
               
 ---
 ### I save result of math expression {string} as {string}
@@ -99,3 +114,43 @@ example:
 When I save result of math expression '{$variable} + 42' as 'result'
 When I save result of math expression '{$random()} * 100' as 'result'
 ```
+
+---
+### I save json to memory as {string}: [Multiline]
+
+Save json value to memory (as JS object)
+
+| param |  type  |      description       |      example      |
+|:-----:|:------:|:----------------------:|:-----------------:|
+|  key  | string |          key           |                   |
+| json  | string | multi string with json | {"key" : "value"} |
+
+example:
+```gherkin
+When I save json to memory as 'object':
+    """
+    {
+        "someKey": "someValue",
+        "otherKey": 42
+    }
+    """
+Then I expect '$object.someKey' to equal 'someValue'
+```
+
+---
+### I save key-value pairs to memory as {string}: [DataTable]
+
+Save key-value pairs provided as Data Table to memory (as JS object)
+
+| param |  type  |   description   | example |
+|:-----:|:------:|:---------------:|:-------:|
+|  key  | string |       key       |         |
+|  kv   | string | key-value pairs |         |
+
+example:
+```gherkin
+When I save key-value pairs to memory as 'key':
+    | someKey      | 42               |
+    | someOtherKey | $valueFromMemory |
+Then I expect '$object.someKey' to equal '42'
+```