Updated docs

Added helpful info to Sponsors section

Author: piotrwitek

Diff for: README.md

@@ -32,6 +32,9 @@ You should check out Playground Project located in the `/playground` folder. It
 [CONTRIBUTION.md](/CONTRIBUTION.md)
 
 ### Sponsor
+> If you like what we're doing here, you can help us by funding the work on specific issues that you choose by using IssueHunt.io!
+> This gives you the power to prioritize our work and support project contributors. Moreover it'll guarantee the project will be updated and maintained in the long run.
+
 [![issuehunt-image](https://github.com/BoostIO/issuehunt-materials/blob/master/[email protected]?raw=true)](https://issuehunt.io/repos/76996763)
 
 ---

Diff for: docs/markdown/2_redux.md

@@ -27,7 +27,7 @@ export type State = {
 };
 ```
 
-Readonly modifier allow initialization, but will not allow rassignment by highlighting compiler errors
+Readonly modifier allow initialization, but will not allow reassignment by highlighting compiler errors
 ```ts
 export const initialState: State = {
   counter: 0,

Diff for: docs/markdown/_intro.md

@@ -30,3 +30,9 @@ You should check out Playground Project located in the `/playground` folder. It
 
 ### Contribution Guide
 [CONTRIBUTION.md](/CONTRIBUTION.md)
+
+### Sponsor
+> If you like what we're doing here, you can help us by funding the work on specific issues that you choose by using IssueHunt.io!
+> This gives you the power to prioritize our work and support the project contributors. Moreover it'll guarantee the project will be updated and maintained in the long run.
+
+[![issuehunt-image](https://github.com/BoostIO/issuehunt-materials/blob/master/[email protected]?raw=true)](https://issuehunt.io/repos/76996763)